IC socket

ABSTRACT

An IC socket is provided with a core block and a plurality of floating members or separating members for forming a plurality of rows each including a multitude of contact pins. For example, base sections of a plurality of first contact pins are fitted between a plurality of ribs formed on an upper surface of the core block, and base sections of a plurality of second contact pins are fitted between a plurality of ribs formed on a lower surface of the core block. 
     A first floating member and a second floating member are integrally displaceable in horizontal directions, and contact portions of the first contact pins and contact portions of the second contact pins are fitted respectively between a plurality of ribs formed on the first floating member and between a plurality of ribs formed on the second floating member. The IC socket is suitable for testing of IC devices having multitude of lead terminals arranged at fine pitch.

PRIOR APPLICATIONS

This application is a division of application Ser. No. 08/585,300, filedJan. 11, 1996, now U.S. Pat. No. 5,788,513 and based on Japanesepriority applications filed in Japan on Jan. 11, 1995 No. 7-2766, onJan. 13, 1995, No. 7-4370, on Jan. 17, 1995, (No. 7-22241, on Mar. 2,1995, No. 7-43067 and on Mar. 7, 1995, No. 7-46921, the contents of theparent and those Japanese applications being incorporated hereinto byreference.

BACKGROUND OF THE INVENTION

A) Field of the Invention

The present invention relates to an IC socket used for inspection of ICdevices, such as IC packages, and specifically to an IC socket usablefor inspection of IC packages having a plurality of lead terminalsarranged at a fine pitch.

B) Description of Prior Art

An IC socket has a number of contact members, known as contact pins,arranged at the same pitch as that of a lead terminal array of an ICdevice to be tested. Each contact pin is formed to be brought intocontact, at one end thereof, with a lead terminal of an IC device, whilethe other end of the contact pin is made to be electrically connectedwith a printed circuit board on which the IC socket is to be mounted. Inorder to assure steady contact of the IC device end of a contact pinwith a lead terminal of the IC device loaded in the IC socket, there isformed a spring section between the IC-device end and the circuit-boardend of the contact pin to allow the IC-device end to be movable. Thecontact pin usually is made to have a thickness of more than 0.1 mm,because a thinner contact pin would have difficulty in creatingsufficient elastic force in the spring section. Usually, a thin divisionwall (hereinafter referred to as a rib) is provided near the IC-deviceend of each contact pin so that adjacent contact pins do not contact oneanother. In some cases, these ribs are integrally formed with the ICsocket body out of synthetic resin. In recent years, however, a separateassembly of synthetic resin, in which a plurality of ribs are arranged,is joined to the IC socket body. Such an assembly is called a floatingmember, for it is reciprocated in a direction of insertion/removal of ICdevices each time one IC device is replaced by another. When ribs havingapproximately 3 mm height are to be formed in one row, 0.2-0.3 mm isusually considered as a lower limit thickness of the ribs. There are,however, many problems to be solved in manufacturing ribs havingthickness and inter-rib size less than this limit value and thus priorattempts to provide an inexpensive IC socket have been unsuccessful.

On the other hand, IC devices have been developed so as to be furtherintegrated and further reduced in size, thus rapidly making their leadterminals arranged at more and more fine pitch. At the present stage,development of IC sockets cannot keep pace with the rapid compact-sizingof IC devices as to provide practical and inexpensive IC sockets forinspecting the IC devices. Therefore, in order to ease adaptation of anIC socket solutions have been proposed in which lead terminals,specifically those of TAB (Tape Automated Bonding) packages are extendedto have otherwise unnecessary length and an arranged zigzag in two rowsaround four sides of the IC chip, as disclosed by Japanese PatentPreliminary Publication No. Hei 6-188339, thereby making interterminalpitch per row less fine. Such an arrangement, however, does not providea satisfactory solution, thus TAB packages in which lead terminals arean arranged zigzag in three or four rows are under consideration.

A primary cause which prevents development of a practical andinexpensive IC socket for inspection is that it is difficult to formpractical ribs to be used as mentioned above out of synthetic resin.Recent IC devices may have, at finest, the interterminal pitch of0.2-0.25 mm, with lead terminals of 0.1-0.15 mm width, which sizesubstantially coincides with the thickness of the contact pins of the ICsocket above-mentioned. Accordingly, the airspace between adjacent leadterminals becomes 0.1-0.15 mm. Therefore, it is physically impossible toform the ribs having the above mentioned thickness so that they areaccommodated in these airspaces.

To enable an IC socket to cope with the fine interterminal pitch of ICdevices, two typical methods are conventionally known. According to onemethod, contact pins themselves are processed so that an insulating filmis locally formed on one side or both sides thereof, while no memberintervenes between the contact pins. According to another method, a thinmetal plate of 0.6 mm thickness having a polyamide film glued on one orboth surfaces thereof, is arranged between contact pins.

To apply the former method, in the first process, pieces shaped ascontact pins are stamped by a press machine out of a hoop material onwhich an insulating film is locally formed in such a manner that thepieces are not completely cut away off the hoop material. Then a platedlayer is formed without break over a predetermined portion of the piecesas contact pins by plating. In the last process, the pieces arecompletely cut away off the hoop material to form individual unitdevices. As described above, this method involves a considerable numberof manufacturing processes. Moreover, process control of this method forassuring uniform thickness over an entire contact pin is very difficult,because the insulating film is liable to bend off. On the other hand,since the latter method requires the thin minute metal plates to befixed one by one manually, assembly costs can increase dramatically.

SUMMARY OF THE INVENTION

A primary object of the present invention is to provide an IC socketwhich allows contact pins to be steadily attached thereto in an array ofless than 0.2 mm pitch width, upon taking the processing fineness andthe strength of ribs formed of synthetic resin into consideration.

Another object of the present invention is to provide a reliable ICsocket free from erroneous operation, in spite of contact pins thereofarranged at a fine pitch.

Still another object of the present invention is to provide an IC socketwhich can be manufactured at relatively low cost, in spite of contactpins thereof arranged at a fine pitch.

In order to attain the above mentioned objects, an IC socket accordingto the present invention includes: a separator member having a firstribs-row formed on one side face thereof and a second ribs-row formed onthe opposite side face thereof, ribs in the first ribs-row and ribs inthe second ribs-row being arranged to keep an alternate positionalrelationship; a plurality of first contact pins with elasticity, eachhaving its free end section, which forms a contact portion at an end,engaged between the ribs in the first ribs-row; a plurality of secondcontact pins with elasticity, each having its free end section, whichforms a contact portion at an end, engaged between the ribs in thesecond ribs-row, wherein the separator member is floatingly held by thefirst contact pins and the second contact pins.

Also according to the present invention, an IC socket comprises: aseparator member having a first ribs-row formed on one side face thereofand a second ribs-row formed on the opposite side face thereof, ribs inthe first ribs-row and ribs in the second ribs-row being arranged tokeep an alternate positional relationship; a core plate member fixed toa socket body and having a third ribs-row and a fourth ribs-row formedon each of surfaces thereof opposite to each other so that ribs in thethird ribs-row and ribs in the fourth ribs-row are arranged to keep analternate positional relationship; a plurality of first contact pinseach being substantially U-shaped as having two legs, the two legshaving respective engagement portions to be engaged between the ribs inthe third ribs-row on the respective surfaces of the core plate member,one of the legs forming a contact portion at a free end section thereof,and the other leg having a connecting terminal; a plurality of secondcontact pins each being substantially U-shaped as having two legs, thetwo legs having respective engagement portions to be engaged between theribs in fourth ribs-row on the respective surfaces of the core platemember, one of the legs forming a contact portion at a free end sectionthereof, and the other leg having a connecting terminal, wherein thefree end sections of the first contact pins and the free end sections ofthe second contact pins are engaged respectively between the ribs in thefirst ribs-row and between the ribs in the second ribs-row of theseparator member so as to hold the separator member.

Also in an IC socket according to the present invention, the firstcontact pins and the second contact pins are arranged on the socket bodyso as to lie on their lateral side of U shape, the separator member islocated so that each rib included in the first and second ribs-rows runsvertically, each free end section of the first and second contact pinsis provided with abutting portions which are allowed to meet theseparator member respectively from the upper side and from the lowerside of the separator member. Also in an IC socket according to thepresent invention, the substantial U-shape of the first contact pins isformed larger than that of the second contact pins, the first ribs-rowand the second ribs-row formed on each of the surfaces of the core platemember are located close to each other, the connecting terminals of thefirst contact pins and the second contact pins are formed at suchpositions as to avoid side-by-side arrangement of connecting terminalsof adjacent contact pins, and an escape section is formed on one of thelower side leg of the first contact pin and the connecting terminal ofthe second contact pin so as to avoid mutual contact.

Also in an IC socket according to the present invention, the contactportions of the first contact pins and the contact portions of thesecond contact pins are arranged in two separate rows to form a zigzagarray as a whole.

In order to attain the above mentioned objects, an IC socket accordingto the present invention includes: a floating member mounted to a socketbody so as to be vertically displaceable relative thereto and providedwith a first ribs-row and a second ribs-row which include a plurality ofribs arranged to keep an alternate positional relationship between thetwo rows; a core block fixed to the socket body at a position under thefloating member and having a first mount face and a second mount face; aplurality of first contact pins each forming a spring section between afree end section having a contact portion and a base section having aconnecting terminal, the free end section of the first contact pin beingfitted between the ribs in the first ribs-row, and the base section ofthe first contact pin being mounted on the first mount face of the coreblock; a plurality of second contact pins each forming a spring sectionbetween a free end section having a contact portion and a base sectionhaving a connecting terminal, the free end section of the second contactpin being fitted between the ribs in the second ribs-row, and the basesection of the second contact pin being mounted on the second mount faceof the core block.

Also in an IC socket according to the present invention, a plurality ofthe core blocks are arranged on the circumference of a body of an ICdevice loaded, each of the core blocks being constructed as a memberforming its longer side in each direction along the ribs-rows of thefloating member with the first mount face and the second mount facebeing formed on surfaces thereof opposite to each other, and thefloating member comprises a first floating member having the firstribs-row and a second floating member having the second ribs-row, thefirst floating member being mounted to the socket body so as to bevertically displaceable relative thereto and the second floating memberbeing integrally fixed to the first floating member.

In order to attain the above mentioned objects, an IC socket accordingto the present invention includes: a floating member mounted to thesocket body so as to be vertically displaceable relative thereto andhaving an opening corresponding to a region where lead terminals of anIC device are arranged zigzag in three or more rows; a plurality ofcontact pins, each of which forms a spring section between a free endsection having a contact portion to be brought into contact with a leadterminal of the IC device through the opening of the floating member anda base section having a connecting terminal, arranged so that thecontact portions thereof form a zigzag array in three or more rows; anda core block mounted on the socket body at a position under the floatingmember, wherein the core block includes a plurality of plate pieceslayered, and a plurality of ribs are formed on each of selected surfacesof the plate pieces, which are selected to correspond to respective rowsof the zigzag array of the contact pins, for regulating intervalsbetween base sections of contact pins arranged in a same row.

Also in an IC socket according to the present invention, phases of pitchof the ribs are orderly shifted among the selected surfaces of the platepieces by a pitch width of the entire array of the contact pins inaccordance with the order of zigzag arrangement of the contact pins.

Also in an IC socket according to the present invention, the core blockcomprises layers of a plate piece forming the ribs on its upper andlower surfaces and a plate piece forming the ribs on its upper or lowersurface, or comprises layers of plate pieces each forming the ribs onupper or lower surface of the same, or alternatively, comprises layersof plate pieces each forming the ribs on upper and lower surfaces of thesame. On an outer side face of each of the plate pieces, a plurality ofvertical ribs are formed for regulating intervals between springsections of contact pins in one row, which row is held to the outer sideface of the plate piece.

Also in an IC socket according to the present invention, the socket bodyincludes a base plate mounting the core block and an enclosure wallenclosing the outer side of the core block, inside face of the enclosurewall being provided with a plurality of vertical ribs for regulatingintervals between spring sections of contact pins in one row held to theenclosure wall.

In order to attain the above mentioned objects, an IC socket accordingto the present invention includes: a floating member forming a ribs-rowalong at least one longitudinal side edge of its slot and mounted to asocket body so as to be displaceable relative thereto; a plurality ofcontact pins, each of which has a free end section having a contactportion, a base section having a connecting terminal for an externalcircuit and a spring section formed between the free end section and thebase section, arranged so that the contact portions thereof are arrangedin separate rows to form a plurality of pins-rows; and at least oneseparator member having a first ribs-row and a second ribs-row arrangedwith their phases being mutually shifted and respectively engaged withtwo of the pins-row so that the separator member is held thereby andtherebetween, wherein the contact portions of contact pins in at leastone of the two pins-rows holding the separator member therebetween areengaged with the ribs-row of the floating member and the contactportions of at least one of the remaining pins-rows are inserted in theslot of the floating member.

Also, an IC socket according to the present invention includes: afloating member forming a ribs-row along one side edge of its slot andmounted to a socket body so as to be displaceable relative thereto; aplurality of contact pins, each of which has a free end section having acontact portion, a base section having a connecting terminal for anexternal circuit and a spring section formed between the free endsection and the base section, arranged so that the contact portionsthereof are arranged in separate rows to form a first pins-row and asecond pins-row; and a separator member having a first ribs-row and asecond ribs-row arranged with their phases being mutually shifted andrespectively engaged with the first pins-row and the second pins-row sothat the separator member is held thereby and therebetween, wherein thecontact portions of the contact pins in the first pins-row are engagedwith the ribs-row of the floating member and the contact portions of thecontact pins in the second pins-row are inserted in the slot of thefloating member.

Also, an IC socket according to the present invention includes: afloating member having a first ribs-row and a second ribs-row formedrespectively along respective side edges of its slot with their phasesbeing mutually shifted, and mounted to a socket body so as to bedisplaceable relative thereto; a plurality of contact pins, each ofwhich has a free end section having a contact portion, a base sectionhaving a connecting terminal for an external circuit and a springsection formed between the free end section and the base section,arranged so that the contact portions thereof are arranged in separaterows to form a first, second and third ribs-rows; and a separator memberhaving a third ribs-row and a fourth ribs-row arranged with their phasesmutually shifted and respectively engaged with one of the first pins-rowand the third pins-row and the second pins-row so that the separatormember is held thereby and therebetween, wherein the contact portions ofthe contact pins in the first pins-row are engaged with the firstribs-row of the floating member, the contact portions of the contactpins in the second pins-row are inserted in the slot of the floatingmember, and the contact portions of the contact pins in the thirdpins-row are engaged with the row of the second ribs-row of the floatingmember.

In order to attain the above mentioned objects, an IC socket accordingto the present invention includes a plurality of contact pins, each ofwhich is approximately U shaped as having a first leg provided with acontact portion to be brought into contact with electronic devices, asecond leg provided with a connecting terminal for an external circuitand a spring section provided between the first leg and the second leg,arranged so that the contact portions thereof are arranged in separaterows to form a plurality of pins-rows, wherein the first leg of theplurality of contact pins are shiftedly located among the pins-rows in adirection substantially parallel to each of the rows. Even if torsion isapplied to the contact pins in accordance with loading of an electronicdevice, this configuration prevents the contact pins from mutualcontact.

Also in an IC socket according to the present invention, the pluralityof contact pins are shaped so that an interval between the first leg andthe second leg of each contact pin in at least one pins-row is equal toor different from that of each contact pin in another one of thepins-rows, and contact pins in at least one of the plurality ofpins-rows and contact pins in another one of the pins-rows are allowedto be mounted to the core block, which is to be fixed to the socketbody, with their respective second legs fitted respectively between aplurality of ribs formed on one surface of the core block and between aplurality of ribs formed on another surface of the core block. Thisconfiguration allows the plurality of contact pins to be mounted to thesocket body after being mounted to the core block, thus the assemblingwork is reduced to be simple.

These and other objects as well as features and advantages of thepresent invention will become apparent in the following description ofthe preferred embodiments when taken in conjunction with theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view of an IC socket according to one embodiment of thepresent invention with its cover removed.

FIG. 2 is a sectional view of the IC socket of the FIG. 1 embodimenttaken along the line "II--II" of FIG. 1, illustrating a state where thecover is closed upon loading of an IC device.

FIG. 3 is a plan view of a socket body according to the FIG. 1embodiment.

FIG. 4 is a plan view of a core plate according to the FIG. 1embodiment.

FIG. 5 is a sectional view taken along the line "V--V" of FIG. 4.

FIG. 6 is an enlarged view of the part enclosed in the ellipse I of FIG.4.

FIG. 7 is a plan view of an inner floating member according to the FIG.1 embodiment.

FIG. 8 is a right-side view of the inner floating member shown in FIG.7.

FIG. 9 is a plan view of an outer floating member according to the FIG.1 embodiment.

FIG. 10 is a right-side view of the outer floating member shown in FIG.9.

FIG. 11 is a plan view of a separator member according to the FIG. 1embodiment.

FIG. 12 is an end-side view of the separator member shown in FIG. 11.

FIG. 13 is an enlarged view of the part enclosed in the ellipse I ofFIG. 3, showing contact pins mounted to the socket body also.

FIG. 14 is a sectional view, as an analogue of FIG. 2, of the IC socketaccording to the FIG. 1 embodiment when taken along the line "XIV--XIV"of FIG. 13.

FIG. 15 is a sectional view, as an analogue of FIG. 2, of the IC socketaccording to the FIG. 1 embodiment when taken along the line "XV--XV" ofFIG. 13.

FIG. 16 is a sectional view, as an analogue of FIG. 2, of the IC socketaccording to the FIG. 1 embodiment when taken along the line "XVI--XVI"of FIG. 13.

FIG. 17 is a sectional view, as an analogue of FIG. 2, of the IC socketaccording to the FIG. 1 embodiment when taken along the line"XVII--XVII" of FIG. 13.

FIG. 18 is a sectional view, as an analogue of FIG. 2, of the IC socketaccording to the FIG. 1 embodiment when taken along the line"XVIII--XVIII" of FIG. 13.

FIG. 19 is a sectional view, as an analogue of FIG. 2, of the IC socketaccording to the FIG. 1. embodiment when taken along the line "XIX--XIX"of FIG. 13.

FIG. 20 is an enlarged view as an analogue of FIG. 13, while showingcontact pins having different shapes.

FIG. 21 is a sectional view, as an analogue of FIG. 2, of an IC socketaccording to another embodiment of the present invention, illustrating astate where its cover is closed upon loading of an IC device.

FIG. 22 is a plan view of a socket body according to the FIG. 21embodiment, showing only one of core blocks being fixed thereto.

FIG. 23 is an enlarged view of the part enclosed in the ellipse I ofFIG. 22.

FIG. 24 is a right-side view of the core block shown in FIG. 23.

FIG. 25 is a bottom plan view of the core block shown in FIG. 23.

FIG. 26 is a sectional view of the core block taken along the line"XXVI--XXVI" of FIG. 23.

FIG. 27 is a sectional view of the core block taken along the line"XXVII--XXVII" of FIG. 23.

FIG. 28 is a sectional view of the core block taken along the line"XVIII--XVIII" of FIG. 23.

FIG. 29 is a plan view of a first floating member according to the FIG.21 embodiment.

FIG. 30 is a right-side view of the first floating member shown in FIG.29.

FIG. 31 is a plan view of a second floating member according to the FIG.21 embodiment.

FIG. 32 is a right-side view of the second floating member shown in FIG.31.

FIG. 33 is an enlarged partial plan view illustrating the first floatingmember and the second floating member of the FIG. 21 embodimentintegrally fixed to each other.

FIG. 34 is a sectional view taken along the line "XXXIV--XXXIV" of FIG.33.

FIG. 35 is a sectional view taken along the line "XXXV--XXXV" of FIG.33.

FIGS. 36A-36F are side views of types of contact pins used for the FIG.21 embodiment to show their shapes.

FIG. 37 is a sectional view, as an analogue of FIG. 2, of an IC socketaccording to still another embodiment of the present invention,illustrating a state where its cover is closed upon loading of an ICdevice.

FIG. 38 is a sectional view taken along the line "XXXVIII--XXXVIII" ofFIG. 37.

FIG. 39 is a sectional view taken along the line "XXXIX--XXXIX" of FIG.37.

FIG. 40 is a plan view of a floating member according to the FIG. 37embodiment.

FIG. 41 is a sectional view taken along the line "XLI--XLI" of FIG. 40.

FIGS. 42A-42C are side views of types of contact pins used for the FIG.37 embodiment to show their shapes.

FIGS. 43A-43B are plan views of separator members used for the FIG. 37embodiment.

FIG. 44A is a sectional view taken along the line "XLIVa--XLIVa" of FIG.43A.

FIG. 44B is a sectional view taken along the line "XLIVb--XLIVb" of FIG.43B.

FIG. 45 shows one arrangement example of lead terminals of TAB package.

FIG. 46 is a sectional view taken along the line "XLVI--XLVI" of FIG.47.

FIG. 47 is a sectional view taken along the line "XLVII--XLVII" of FIG.46.

FIG. 48 is a sectional view as an analogue of FIG. 38, showing oneexample of core block modification according to the FIG. 37 embodiment.

FIG. 49 is a sectional view as an analogue of FIG. 38, showing anotherexample of core block modification according to FIG. 37 embodiment.

FIG. 50 is a sectional view as an analogue of FIG. 38, showing stillanother example of core block where contact pins are arranged in fourrows to form a zigzag pattern.

FIG. 51 is a sectional view as an analogue of FIG. 46, showing oneexample of separator member where contact pins are arranged in four rowsto form a zigzag pattern.

FIG. 52 is a sectional view, as an analogue of FIG. 2, of an IC socketaccording to a further additional embodiment of the present invention,illustrating a state where its cover is closed upon loading of an ICdevice.

FIG. 53A is a plan view of a floating member according to the FIG. 52embodiment.

FIG. 53B is a sectional view taken along the line "LIII--LIII" of FIG.53A.

FIG. 54 is an enlarged sectional view of the main part of the IC socketaccording to the FIG. 52 embodiment.

FIG. 55A-55C are side views of types of contactpins used for the FIG. 52embodiment to show their shapes.

FIG. 56 shows a separator member according to the FIG. 52 embodiment.

FIG. 57 illustrates relationship among a floating member, contact pinsand a separator member according to the FIG. 52 embodiment.

FIG. 58 is a sectional view taken along the line "LVIII--LVIII" of FIG.57.

FIG. 59 illustrates relationship among a floating member, contact pinsand a separator member according to an embodiment different from that ofFIG. 52.

FIG. 60 is a sectional view taken along the line "LX--LX" of FIG. 59.

FIG. 61 is a sectional view as an analogue of FIG. 60, illustratingrelationship among a floating member, contact pins and separator membersaccording to an embodiment different from those of FIG. 52 and FIG. 59.

FIG. 62A is a plan view of a main part of a block body mounting contactpins according to an embodiment which has a mounting configurationdifferent from that of the FIG. 21 embodiment.

FIG. 62B is a sectional view taken along the line "LXII--LXII" of FIG.62A.

FIG. 62C is a right-side view of the configuration shown in FIG. 62B.

FIG. 63A is a plan view of a main part of a block body mounting contactpins according to an embodiment which has a mounting configurationdifferent from those of the FIG. 21 and FIG. 62 embodiments.

FIG. 63B is a sectional view taken along the line "LXIII--LXIII" of FIG.63A.

FIG. 63C is a right-side view of the configuration shown in FIG. 63B.

FIG. 64A is a plan view of a main part of a block body mounting contactpins according to an embodiment which has a mounting configurationdifferent from those of the FIG. 21, FIG. 62A and FIG. 63A embodiments.

FIG. 64B is a sectional view taken along the line "LXIV--LXIV" of FIG.64A.

FIG. 64C is a right-side view of the configuration shown in FIG. 64B.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Through the following description of embodiments, identical symbols willdenote substantially identical or similar members.

One embodiment of the present invention will be described using FIG. 1through FIG. 20.

This embodiment is shown as an IC socket for above-mentioned TABpackages. Although the TAB package is so well known as to need nodetailed explanation, its configuration is roughly described as follows.In the TAB package, as shown in FIG. 2, a square IC chip T is located inthe center of a printed wiring film PCB which is provided with aplurality of lead terminals arranged along four sides thereof, and theTAB package has a frame CA which is denominated "carrier" on the foursides of the film for convenience in handling during manufacturing.

The lead terminals of the TAB package, not apparently seen in thedrawing, are arranged in two rows along each side of the frame CA so asto be alternately positioned to form a zigzag array. At positions on theperiphery of the frame CA, three notches not shown in the drawing areformed for allowing the package to be loaded in an IC socket in apredetermined posture without erroneous positioning.

The printed wiring film PCB has reference holes formed in foursubstantial comers near the frame CA, for limiting its position whenloaded.

According to the embodiment, for the loading of such a TAB package, acover 2 is attached to a socket body 1 in such a manner as allowsopening-closing operation. Specifically, the socket body 1 is providedwith a shaft 1b shown in FIG. 2 which is fitted in two holes 1a shown inFIG. 1, and a cover frame 2A and a pressing plate 2B are mounted to theshaft 1b to be enabled to swing. The cover frame 2A is urged by a springnot shown in the drawings in a counterclock wise direction on the figuresurface of FIG. 2. A hook member 2C is mounted to a shaft 2A1, which isprovided at an end section of the cover frame 2A, to be enabled to swingand is urged by a spring 2A2 in a clockwise direction. While FIG. 2shows a state where the loading condition is maintained by engagement ofa hook portion 2CI of the hook member 2C with a hook portion 1c of thesocket body 1, the engagement is released and the cover 2 is opened whenthe hook member 2C is pushed from upside against the spring 2A2.

The pressing plate 2B is mounted to the shaft 1b at its slots 2B2, andits end section 2B1 is loosely inserted in a hole 2A3 of the cover frame2A. In an substantial center of the pressing plate 2B, a pressingsection 2B3 is formed for pressing downward the IC chip T of the TABpackage. To the pressing plate 2B, an auxiliary pressing plate 2D havinga through section for the pressing section 2B3 is fitted, for pressingdownward the frame CA of the TAB package.

This structure of the cover frame 2A and the pressing plate 2B isdesigned to moderate force which is obliquely applied to the TAB packageby the swing of the cover 2 during the loading operation of the TABpackage, thereby the pressing force being applied substantially in avertical direction.

As shown in FIG. 2, on the lower side of the socket body 1, a locatingboard 3 is mounted to a middle plate 4, which is fixed to the socketbody, so as to be vertically displaceable relative thereto using pins 3aas guides. To the middle plate 4, a movable stage 6 is attached so as tobe vertically movable via four shafts 5 fixed by caulking. The movablestage 6 is urged upward by springs 7 wound around the shafts 5, with itsupper limit position regulated by flanges 5a of the shafts 5.Twenty-five high heat transfer pins 8 are fixed to the middle plate 4,with ends of bending sections on the upper part thereof being fitted intwenty-five holes 6a shown in FIG. 1 formed in the movable stage 6,while Lower ends thereof piercing through the locating board 3 to beconnected with a printed circuit board not shown, thereby the ends ofthe bending sections being brought into contact with the IC chip T asthe TAB package is loaded so that heat generated at the IC chip T istransferred to the printed circuit board.

The top side of the socket body 1 is shown in FIG. 3, where four holes1d are to be used for mounting to the printed circuit board. D type pins1e are to be fitted in the notches, which are formed on the frame CA ofthe TAB package for preventing the TAB package from erroneous loading asmentioned before. Holes 1f and holes 1g each arranged at four positionsare to be engaged with respective hook portions of an inner floatingmember 10 and an outer floating member 11 described later herewith. Fournon-through holes, or recesses 1h are formed on the socket body 1 to actas guide holes by receiving pins of the later described inner floatingmember 10 to allow vertical movement of the inner floating member 10.Along four sides of the socket body 1, a number of ribs to be engagedwith contact pins and a number of perforations to allow the connectingterminals of the contact pins to pierce the socket body are formed.Their patterns of arrangement will be described later. Four holes 1i areto be used for fixing a core plate, which will be described below, bycaulking.

FIG. 4 shows a top plan view of a core plate 9, FIG. 5 is a sectionalview taken along the line V--V of FIG. 4, and FIG. 6 is an enlarged viewof a part indicated by the ellipse I of FIG. 4. The core plate 9 isfixed to the socket body 1 by caulking upon its four holes 9a beingaligned to the above mentioned four holes 1i of the socket body 1. Inthe core plate 9, three notches 9b for avoiding the pins 1e of thesocket body 1 and four holes 9c to be used for mounting to the printedcircuit board are formed. Also, four holes 9d for insertion of hookportions of the outer floating member 11, which will be described later,therethrough, and guide holes 9e for insertion of guide pins of theouter floating member 11, which also will be described later,therethrough are formed in the core plate 9. In the guide holes 9e,outer sections 9e1 are formed so that coil springs not shown are fittedtherein to urge the outer floating member 11 upward in the state shownin FIG. 2.

As shown in the enlarged views of FIG. 5 and FIG. 6, on a top surface ofthe core plate 9, a plurality of ribs 9f and a plurality of ribs 9g areformed each in one row so that the ribs 9f and the ribs 9g arealternately located. In the similar manner, on a bottom surface of thecore plate 9, a plurality of ribs 9h and a plurality of ribs 9i areformed at respective locations opposite to the ribs 9f and the ribs 9g.Moreover, on the bottom surface of the core plate 9, ribs 9j are formedto correspond to the ribs 9h. Such array of ribs 9f, 9g, 9i, 9j isformed on each of four sides of the core plate 9.

Now, description will be made on the inner floating member 10 mainlyusing FIG. 7 and FIG. 8.

FIG. 7 is a plan view of the inner floating member 10, and FIG. 8 is aright-side view of the same.

The inner floating member 10 is provided with guide pins 10a which arelocated at four positions on a lower section thereof and are fitted inthe holes 1h of the socket body 1, so as to be urged upward by springs10b shown in FIG. 2. Upward movement of the inner floating member 10 islimited by hook portions 10c located at another four positions on thelower section and having their ends fitted in and locked by the holes 1fof the socket body 1.

The outer floating member 11 is shown in FIG. 9 and FIG. 10.

On the lower side of four substantial corners of the outer floatingmember 11, guide pins 11a are provided to be fitted in the holes 9e ofthe core plate 9 and urged upward by springs not shown in the drawingsin the state of FIG. 2. Upward movement of the outer floating member 11which should be caused by the above mentioned springs is limited by hookportions 11b located at another four positions on the lower side of theouter floating member 11 and having their ends fitted in and locked bythe holes 1g of the socket body 1. On the upper side of the foursubstantial comers of the outer floating member 11, reference pins 11care provided to be fitted in the above-mentioned reference holes formedin the printed wiring film PCB of the IC package.

In FIG. 1, four separator members 12 are shown between the innerfloating member 10 and the outer floating member 11. FIG. 11 is a planview of one separator member 12 arranged along a right side in FIG. 1,and FIG. 12 is an end-side view of the separator member 12.

As shown in FIG. 12, a top surface of the separator member is brokeninto a higher level face 12a and a lower level face 12b. Similarly, abottom surface of the separator member 12 is broken into a higher levelface 12c and a lower level face 12d, a plurality of ribs 12e and aplurality of ribs 12f are respectively formed on a right side face and aleft side face of the separator member 12 each in their respectivesingle rows substantially from end to end of the separator member insuch a manner that the ribs 12e and the ribs 12f are alternatelylocated. The separator member 12 is held by and between a plurality offirst contact pins 13 and a plurality of first contact pins 14, whichwill be described next.

Now, shapes of the contact pins and engagement relationship betweenthese contact pins and respective ribs will be detailed. In FIG. 13, apart of the rib section (indicated by the ellipse II) of the socket body1 roughly illustrated in FIG. 3 is enlarged to show the state where theplurality of first contact pins 13 and the plurality of second contactpins 14 are alternately engaged between the ribs. FIGS. 14-19 aresectional views respectively taken along the lines XIV--XIV throughXXIX--XXIX of FIG. 13, drawn in the manner similar to FIG. 2. As shownin FIG. 2, the first contact pins 13 and the second contact pins 14 aresubstantially U-shaped and arranged in the socket body so as to lie ontheir lateral side of U shape.

A part of FIG. 2 is enlarged to appear in detail in FIG. 14. Thus,structure of the first contact pins 13 and the second contact pins 14will be described mainly using FIG. 14. Each of the first contact pins13 has a spring section 13a urging engagement portions 13d and 13e,which are respectively formed on two legs 13b and 13c, to hold the coreplate 9 therebetween. The spring sections 13a are engaged between aplurality of L-shaped ribs 1j formed on the socket body. As shown inFIG. 13, every third ribs ij have their horizontal sections formedlonger than the remainings of the ribs 1j. On the other hand, theengagement portions 13d and 13e are engaged respectively between theribs 9f and between the ribs 9h formed on the core plate 9. Thestructure including the spring section 13a is advantageous where thecore plate 9 is set into the socket body 1 upon the contact pins 13preliminarily being attached to the core plate 9.

Free end sections of the legs 13b are shaped to rise vertically to beengaged between the ribs 12e of the separator member 12.

On each leg 13b, formed are an abutting portion 13f and an abuttingportion 13g which are allowed to meet an upwardly directed face 12a anda downwardly directed face 12c of the separator member 12 respectively,and at an end of the leg 13b, a contact portion 13h is formed to bebrought into contact with a lead terminal formed on the printed wiringfilm PCB. As shown in FIG. 13, the other legs 13c of the first contactpins 13 are engaged between a plurality of ribs 1k and between aplurality of ribs 1j formed on the socket body 1, with their endsengaged between the ribs 9j of the core plate 9. Every third ribs 1k andevery third ribs 1m are respectively made longer than the respectiveremainings of the ribs 1k and the ribs 1m. As shown in FIG. 13, phasesof repetitive appearance of the longer horizontal sections of the ribs1j, the longer ribs 1k, and the longer ribs 1m are shifted among rowsformed by these ribs.

Furthermore, on each of the legs 13c of the first contact pins 13, aconnecting terminal 13i is formed. The connecting terminals 13i piercethe socket body 1 and the locating board 3, to be electrically connectedto connecting terminals (land) formed on a printed circuit board onwhich the IC socket of this embodiment is mounted.

According to this embodiment, three types of the first contact pins 13having different shapes are used. They are different in the positionwhere the connecting terminal 13i is formed. The first contact pin 13showing its entire shape in FIG. 14 corresponds to the pin 13 drawnnearest from the bottom of the figure in FIG. 13. As seen from the FIG.13, the connecting terminals 13i of the contact pins 13 are arranged soas to be orderly shifted in a longitudinal direction of the legs 13cwith appearance of the three types of the contact pins 13 as one cycleof repetition. Entire shapes of the three types of the first contactpins 13 are shown in FIGS. 14, 16, 18.

Next, description will be made on the second contact pins 14.

As shown in FIG. 14, the second contact pins 14 are formed to have Ushape smaller than that of the first contact pins 13. This configurationis adopted, upon the narrow intervals between the contact pinscorresponding to the fine pitch arrangement of the lead terminals of theTAB package being taken into consideration, for the purpose of avoidingmutual contact of adjacent contact pins bent during the loading of theTAB package. Each of the second contact pins 14 has a spring section 14aurging two legs 14b, 14c to hold the core plate 9 therebetween, where anengagement portion 14d formed on the leg 14b is engaged between the ribs9g formed on the core plate 9. The structure including the springsection 14a also is so advantageous for assembling work as theequivalent structure of the first contact pins 13 is.

Free end sections of the legs 14b are shaped to rise vertically to beengaged between the ribs 12f of the separator member 12.

On each leg 14b, formed are an abutting portion 14e and an abuttingportion 14f which are allowed to meet an upwardly directed face 12b anda downwardly directed face 12d of the separator member 12 respectively,and at an end of the leg 14b, a contact portion 14g is formed to bebrought into contact with a lead terminal formed on the printed wiringfilm PCB. Even when the TAB package is loaded and the contact pins arebent, the leg 14b can surely avoid contact with the engagement portions13b of adjacent contact pins 13, because the ribs 9f and the ribs 9g arevery closely located. The other legs 14c of the second contact pins 14are engaged between the ribs 9i formed on the core plate 9.

Furthermore, on each of the legs 14c of the second contact pins 14, aconnecting terminal 14h is formed. The connecting terminals 14h piercethe socket body 1 and the locating board 3, similar to the connectingterminals 13i, to be electrically connected to connecting terminals(land) formed on the printed circuit board. As the second contact pins14 also, used are three types of contact pins different in the positionwhere the connecting terminal 14h is formed. The second contact pins 14are arranged between the first contact pins 13. Arrangement pattern ofthe connecting terminals 14h of the second contact pins 14 is shown inthe sectional view FIG. 13.

As shown in FIG. 13, the connecting terminals 14h of the contact pins 14also are arranged so as to be orderly shifted in a longitudinaldirection of the legs 14c with appearance of the three types of thecontact pins 14 as one cycle of repetition. Entire shapes of the threetypes of the second contact pins 14 are shown in FIGS. 15, 17, 19.Bending action of the second contact pins 14 accompanying loading of theTAB package is made stabilized upon the respective types of connectingterminals 14h being held to the long ribs on the socket body 1 and endsof the legs 14c shown in FIGS. 15, 17 being held to the socket body 1.

FIG. 20 is a sectional view similar to FIG. 13, illustrating a modifiedshape of the leg 13c of the first contact pins 13. This structure allowsthe legs 13c of the first contact pins 13 to steadily avoid contact withthe connecting terminals 14h of the second contact pins 14.

Although it may be apparent from the foregoing explanations,loading/removing operation of TAB packages according to the presentembodiment will be described briefly. In reference to FIG. 2, when thehook member 2C is pushed from upside against the spring 2A2, the hookportions 1c and 2C1 are disengaged, and the cover 2 is made swingcounterclockwise by force of the spring not shown about the shaft 1b.Then, the TAB package can be taken out of the IC socket manually or bysome machine.

To load the TAB package, at first the TAB package is placed on thesocket body 1 so that the notches formed in the frame (carrier) CA isaligned to the pins 1e, and then the cover 2 is closed to cause thepressing section 2B3 of the pressing plate 2B to press the IC chip T onthe movable stage 6 as well as to cause the auxiliary pressing plate 2Dto press the printed wiring film PCB to the inner floating member 10 andthe outer floating member 11 through pushing the frame CA. Force via thepressing plate 2B acts on the IC chip T substantially in a verticaldirection as a result of relationship between the shaft 1b and the slot2B2 and relationship between the end section 2B1 of the pressing plate2B and the hole 2A3.

As the movable stage 6 moves downward against the springs 7 by thepushing via the pressing section 2B3, the high heat transfer pins 8 arebent and the ends thereof are steadily brought into contact with the ICchip T, whereby heat radiating from the IC chip T during the inspectionis transferred to the printed circuit board. On the other hand, as theinner floating member 10 and the outer floating member 11 are pushed,the inner floating member 10 moves downward against the springs 10b andthe outer floating member 11 also moves downward against springs notshown in the drawings, whereby the lead terminals formed on the printedwiring film PCB are brought into contact with the contact portions 13h,14g of the contact pins 13, 14.

After the lead terminals formed on the printed wiring film PCB arebrought into contact with the contact pins 13, 14, the inner floatingmember 10 and the outer floating member 11 are further pushed until anappropriate contact force is applied to every contact point to assureconnection. Finally, the hook section 2C1 of the hook member 2c isengaged with the hook section 1c of the socket body 1, to assume thestate shown in FIG. 2.

During the operation described above, the separator member 12 also movesdownward along with the contact portions 13h, 14h of the contact pins13, 14, which is an advantageous feature. That is, even if relationshipbetween the contact pins 13 and the ribs 12e or relationship between thecontact pins 14 and the ribs 12f involves slight inconvenience forengagement, all the contact portions 13h, 14g are moved downward,without excessive force being applied thereto, via the separator member12 as the abutting portions 13f, 14e of some of the plurality of contactpins push the upwardly directed faces 12a, 12b of the separator member.

Conventionally, a floating member is structured as a zonal-square-shapedsingle assembly having a plurality of holes formed along each of itsfour sides, and contact portions 13h, 14g of contact pins so arranged asin the present embodiment are fitted in these holes. In thisconfiguration, however, friction is caused between the floating memberand the contact pins 13, 14, because the floating member movesvertically while the contact portions 13h, 14g move upon the engagementportions 13d, 14d functioning as fulcrums. In contrast, according tothis embodiment, the inner floating member 10 and the outer floatingmember 11 are not brought into contact with the contact pins 13, 14, andmoreover, the separator member 12 moves in accordance with the contactpins 13, 14 to cause very little friction; this embodiment is superiorin view of durability.

Although the foregoing descriptions on this embodiment have referred tothe TAB package as an IC device to be loaded in the IC socket, thepresent invention is applicable also to an IC socket for devices havinglead terminals arranged on two sides of the IC chip, not limited to thisexample. Furthermore, while in this embodiment, the contact portions 13hof the contact pins 13 and the contact portions 14g of the contact pins14 are arranged in separate rows, it is needless to say that thesecontact pins may be arranged in a single row by extending one of therows of the contact portions to be aligned to the other row of thecontact portions, because the separator member 12 can be made morecompact so that the ribs 12e and the ribs 12f are located closer to eachother.

Next, referring to FIG. 21 through FIGS. 36A-36F, another embodiment ofthe present invention will be described. As shown in FIG. 21, a knownlocating board 3 is movably mounted to a socket body 1 with an elastichook portion 3', to be located on the lower side of the socket body 1. Amovable stage 6 (drawn with the single dot & dash line) is movablymounted to the socket body 1 as well known in the art. The movable stage6 has four pins 6b which are made fitted in four holes In shown in FIG.22 of the socket body 1 and is urged upward by springs not shown in thedrawings. The upper limit position of the movable state 6 is regulatedby a structure not shown in the drawings but similar to the hook portion3a' of the locating board 3.

Additionally, a plurality of high heat transfer pins (25 pins, forexample) not shown in the drawings are provided between the movablestage 6 and the locating board 3 as having already been described.

As shown in FIG. 22, four holes 1d are formed on the socket body 1 to beused for attachment to the printed circuit board. D type pins 1e are tobe fitted in the notches, which are formed on the frame CA of the TABpackage for preventing the TAB package from erroneous loading asmentioned before.

Holes 1p arranged at four positions are to be engaged with hook portions17b of a first floating member 17 which will be described laterherewith. Four non-through holes, or recesses 1q are formed on thesocket body 1 to act as guide holes by receiving pins 17a of a firstfloating member 17, which will be described later, to allow verticalmovement of the first floating member 17.

Along four sides of the socket body 1, a plurality of perforations 1rare arranged at an uniform pitch in six rows per side so that phases ofthe pitch are shifted between the rows. These perforations 1r are usedto have connecting terminals of contact pins, which will be describedlater, to pierce the socket body 1. Holes 1s are arranged at threepositions per side of the socket body 1 to be used for fixing coreblocks 15, which will be described next, by caulking. FIG. 22 shows astate where a core block 15 is fixed to only one side of the socket bodyby caulking with rivets 16.

Now, description will be made on a structure of the core blocks 15.Since all the four core blocks have an identical structure, thefollowing explanation refers to only one of them. FIG. 23 is an enlargedview of a selected part of the core block 15 indicated by the ellipseIII of FIG. 22, FIG. 24 is a right-side view of the selected part shownin FIG. 23, FIG. 25 is a bottom plan view of the selected part shown inFIG. 23, and FIGS. 26 through 28 are sectional views taken respectivelyalong the lines XXVI--XXVI through XVIII--XVIII of FIG. 23. The coreblock 15 forms three holes 15a at positions at its two longitudinal endsand its longitudinal center corresponding to three holes is on one sideof the socket body 1 so that it is fixed to the socket body 1 bycaulking with the rivets 16 at these positions (In FIGS. 23-25, only oneof the holes 15a is shown).

A plurality of ribs 15b and a plurality of ribs 15c are formed to bearranged at regular intervals respectively on a top surface and a bottomsurface of the core block 15 made of synthetic resin.

As apparently seen in FIG. 24, the ribs 15b (on the top surface) and theribs 15c (on the bottom surface) are alternately positioned. In the coreblock 15, through holes 15d are formed at two or three positions on eachgroove between the ribs 15b through their corresponding positions oneach rib 15c, so that the contact pins are fitted therein. As shown inFIGS. 26-28, the holes 15 are formed to orderly have three types ofshape among the grooves between the ribs 15b.

Now, description will be made on the first floating member 17 and thesecond floating member 18 mainly using FIGS. 29-34. FIG. 29 is a planview of the first floating member 17 and FIG. 30 is a right-side view ofthe same. The first floating member 17 is provided with guide pins 17awhich are located at four positions on a lower side thereof and arefitted in the holes 1q of the socket body 1. At another four positionson the lower side, elastic hook portions 17b are provided to be fittedin the holes 1p of the socket body 1 so as to have their ends engagedwith the holes 1p. The first floating member 17 is urged upward bysprings not shown in the drawings but wound around the guide pins 17a inthe state of FIG. 21, while its upper limit position is regulated by theengagement between the end of the hook portions 17b and the holes 1p. Oneach corner of the first floating member 17, two non-through holes 17cand one non-through hole 17d are formed. Ribs formed on the firstfloating member 17 will be detailed later.

FIG. 31 is a plan view of the second floating member 18 and FIG. 32 is aright-side view of the same. The second floating member 18 iszonal-square-shaped and has four through holes 18a formed on four comersthereof. On a lower side of the second floating member 18, two pins 18bare formed at four substantial comers. FIG. 33 shows a state where thefirst floating member 17 and the second floating member 18 areintegrally fixed to each other by a reference pin 19, upon the pins 18bbeing fitted in the holes 17c. As shown in FIG. 35, the reference pin 19passes through the hole 18a of the second floating member 18 and isthrust into the hole 17d of the first floating member 17. The referencepin 19 is provided to be fitted in a hole formed on the printed wiringfilm PCB of the TAB package.

FIG. 33 corresponds to superposition of the part indicated by thecircle• of FIG. 31 over the part indicated by the circle• of FIG. 29. Asshown in FIG. 33, a slot 17e is formed along each of four sides of thefirst floating member 17, and as shown in FIG. 34, has ribs 17f formedon an upper portion of its inner edge. The ribs 17f are arranged alongeach of the four sides at regular intervals as shown in FIG. 33, tooppose the ribs 15b of the core blocks 15 each to each when the floatingmembers are mounted to the socket body 1.

On the other hand, ribs 18c are formed on inner circumferential foursides of the second floating member 18. The ribs 18c are arranged alongeach of the four sides at regular intervals as shown in FIG. 33, tocorrespond to the ribs 15c of the core blocks 15 each to each when thefloating members are mounted to the socket body 1.

Now, shapes of the contact pins and engagement relationship betweenthese contact pins and respective ribs will be detailed. FIGS. 36A, 36B,36C show three types of first contact pins 20, and FIGS. 37A, 37B, 37Cshow three types of second contact pins 21. Both of the contact pins 20,21 are substantially U-shaped, but the first contact pins 20 have alarger U shape than that of the second contact pins 21. These contactpins 20, 21 are alternately arranged in the socket body so as to lie ontheir lateral side of U shape.

On base sections 20a of the first contact pins 20, connecting terminals20b and protrusions 20c are formed. Positions of the connectingterminals and the protrusion 20c are different among the three types ofthe first contact pins 20 shown in FIGS. 36A, 36B, 36C, and differenceamong them exist also in that the first contact pin 20 shown in FIG. 36Bhas two protrusions 20c. Each of the first contact pins 20 has a springsection 20e and a free end section 20f which rises vertically to formits end as a contact portion. On a base section 21a of each of thesecond contact pins 21, a connecting terminal 21b is formed. Differenceamong the three types of the second contact pins 21 shown in FIGS. 36D,36E, 36F exists only in the position of the connecting terminal 21b.Each of the second contact pins 21 has a spring section 21c and a freeend section 21d which rises vertically to form its end as a contactportion.

Now, assembling processes concerning the contact pins 20, 21 will bedescribed. The contact pins 20, 21 are fixed to the core blocks 15 oneby one. The order of fixing is explained mainly using FIGS. 26-28 andFIGS. 36A-36F. To begin with, a first contact pin 20 shown in FIG. 36Ais fixed such that its base section 20a is fitted in a groove betweenthe ribs 15b with a connecting terminal 20b and a protrusion 20c formedthereon made inserted into the holes 15d shown in FIG. 26. Next, asecond contact pin 21 shown in FIG. 36D is fixed so that its basesection 21a is inserted in a groove between the rib 15c shown in FIG. 26and the rib 15c shown in FIG. 27. Then, in the similar manner, a firstcontact pin 20 shown in FIG. 36B is fixed so that a connecting terminal20b and two protrusions 20c are inserted in the holes 15d shown in FIG.27, that is, the base section 20a is fitted in a groove between the rib15b indicated in FIG. 26 and the rib 15b indicated in FIG. 27. This typeof fixing is shown in FIG. 21.

Next, a second contact pin 21 shown in FIG. 36E is fixed so that itsbase section 21a is inserted in a groove between the rib 15c shown inFIG. 27 and the rib 15c shown in FIG. 28. After that, a first contactpin 20 shown in FIG. 36C is fixed so that a connecting terminal 20b anda protrusion 20c are inserted in the holes 15d shown in FIG. 28, thatis, the base section 20a is fitted in a groove between the rib 15bindicated in FIG. 27 and the rib 15b indicated in FIG. 28. At an end ofthe order, a second contact pin 21 shown in FIG. 36F is fixed so thatits base section 21a is inserted in a groove between the rib 15c shownin FIG. 28 and an adjacent rib 15c behind it. As stated above, thecontact pins 20, 21 are fixed to the core blocks 15 by turns withappearance of these six types shown in FIGS. 36A-36F as one cycle ofrepetition. Consequently, in the state where the fixing of the contactpins 20, 21 to one core block 15 is completed, the contact portions ofthe first contact pins 20 and the contact portions of the second contactpins are arranged in respective single rows along the longitudinaldirection of the core block 15.

After the fixing of the contact pins 20, 21 to the core block 15,connecting terminals 20b, 21b of the contact pins 20, 21 are made passthrough the perforations 1r in the socket body 1 and throughperforations 3b correspondently arranged in the locating board 3. Then,the core block 15 is fixed to the socket body 1 by caulking with therivets 16. The state shown in FIG. 22 where only one of the core blocks15 is fixed by caulking with rivets 16 is illustrated in FIG. 21 also asa sectional view. In the configuration shown in FIG. 21, the firstcontact pin 20 are stable in spite of vertical movement of their contactportions, or of their free end sections 20f. This is not only becausethe connecting terminals 20b are inserted in the holes 15d so that thebase sections 20a are thrust into the grooves between the ribs 15b, butalso because the first contact pins 20 are provided with the protrusions20c inserted in the holes 15d. On the other hand, the base sections 21aof the second contact pins 21 are held by the core block 15 and thesocket body 1 therebetween, to be in a considerably stable condition.However, the second contact pins may be structured to have protrusionssimilar to those of the first contact pins 20 to be fitted in holesformed in the core block 15 or in the socket body 1, or may have theirbase sections 21a held between ribs formed on the socket body 1. Ofcourse, some cases only requires that the base sections 21a are thrustinto the grooves between the ribs 15c. In other words, according to thisembodiment, it is not a necessary configuration that the base sections21 a is held by the core block 15 and the socket body 1 therebetween; anairspace may be provided between the base sections 21a and the socketbody 1.

In the next assembling stage, the integral body including the firstfloating member 17 and the second floating member 18 preliminarily fixedtogether with the reference pins 19 is set in its position with the hookportions 17b of the first floating member 17 being engaged with theholes 1p of the socket body 1. On this occasion, the contact portions atthe ends of the free end sections 20f of the first contact pins 20 aremade fitted between the ribs 17f and the contact portions at the freeend sections 21d of the second contact pins 21 are made fitted betweenthe ribs 18c. Of course, another order of assembling is possible, where,at first, the first floating member 17 is set in its place to make thecontact portions of the contact pins 20 fitted between the ribs 17f,then the second floating member 18 is placed upon the first floatingmember 17 to make the contact portions of the contact pins 21 fittedbetween the ribs 18c, and at last, the first floating member 17 and thesecond floating member 18 are integrally fixed together with thereference pins 19. As understood from the above discussion, thisembodiment allows a body including the first floating member 17 and thesecond floating member 18, or a body including the first floating member17, the second floating member 18 and the reference pins 19, to beintegrally formed of synthetic resin.

In the IC socket of this embodiment assembled as described above, thefirst contact pins 20 and the second contact pins 21 are sufficientlyspaced among their respective selves to avoid mutual contact.Furthermore, since the first contact pins 20 and the second contact pins21 are different in size of their U shape, and positional relationshipbetween the vicinity of the free end sections 20f and the vicinity ofthe free end sections 21d, which relationship should be of the greatestconcern, is steadily regulated by the ribs 17f and the ribs 18c arrangedclosed to each other, mutual contact of adjacent contact pins 20 and 21is impossible even if the contact pins bend owing to the spring sections20e, 21c.

Therefore, this configuration is applicable also to an IC socket for ICdevices having lead terminals arranged in one row, not limited to thesocket for IC devices having lead terminals set in a zigzag array. Insuch a case, this embodiment is modified, for example, so that the uppersurfaces of the ribs 17f are lowered to the level indicated by thedouble dot & dash line of FIG. 34 and the free end sections 21d of thesecond contact pins 21 are bent over the ribs 17f so that the contactportions of the second contact pins 21 are aligned to the row of thecontact portions of the first contact pins 20.

Also, while this embodiment adopts the configuration in which the basesections 20a of the first contact pins 20 are thrust into the groovesbetween the ribs 15b formed on the upper surface of the core block 15and the base sections 21a of the second contact pins 21 are thrust intothe grooves between the ribs 15c on the lower surface of the core block15, another configuration is possible in which two core blocks arespacedly arranged one above the other so that the base sections 20a ofthe first contact pins 20 and the base sections 21a of the secondcontact pins 21 are thrust from upside in the same attitude into groovesbetween ribs formed on their respective corresponding core blocks. Ofcourse, if condition allows types of the contact pins to be increased,this configuration is allowed to be further modified so that largernumber of core blocks are spacedly arranged one above another. Also, thecontact pins are allowed to be thrust either into grooves between ribsformed on the respective upper surfaces of the core blocks, or intogrooves between ribs formed on the respective lower surfaces of the coreblocks.

To load the TAB package, at first the TAB package is placed on thesocket body 1 so that the notches formed in the frame (carrier) CA isaligned to the pins 1e, and then the cover 2 is closed to cause thepressing section 2B3 of the pressing plate 2B to press the IC chip T onthe movable stage 6 as well as to cause the auxiliary pressing plate 2Dto press the printed wiring film PCB to the first floating member 17 andthe second floating member 18 through pushing the frame CA. Force viathe pressing plate 2B acts on the IC chip T substantially in a verticaldirection as a result of the configuration of the pressing plate 2Bpivotably supported by the shaft 1b with a play as well as relationshipbetween the end section 2B1 of the pressing plate 2B and the hole 2A3.

As the movable stage 6 moves downward against the springs 7 by thepushing via the pressing section 2B3, ends of known high heat transferpins 8 are steadily brought into contact with the IC chip T, wherebyheat radiating from the IC chip T during the inspection is transferredto the printed circuit board. On the other hand, as the first floatingmember 17 and the second floating member 18 are pushed, they movedownward against the springs not shown in the drawings but wound aroundthe guide pins 17a, whereby the lead terminals formed on the printedwiring film PCB are brought into contact with the contact portionsformed on the ends of the free end sections 20f, 21d of the contact pins20, 21.

After the lead terminals formed on the printed wiring film PCB arebrought into contact with the contact pins 20, 21, the first floatingmember 17 and the second floating member 18 are further pushed until anappropriate contact force is applied to every contact point to assureelectrical connection. Finally, the hook section 2C1 of the hook member2c is engaged with the hook section 1c of the socket body 1, to assumethe state shown in FIG. 21.

Next, referring to FIG. 37 through FIG. 51, still another embodiment ofthe present invention will be described. This embodiment is configuredto be applied to TAB packages whose lead terminals are arranged in threerows to form a zigzag array as shown in FIG. 45.

As understood from FIGS. 37-41, above a base plate of a socket body 1, afloating member 22 is mounted to the socket body 1 so as to bevertically displaceable relative thereto. The floating member 22 hasfour openings 22a corresponding to regions of the TAB package where leadterminals F1, F2, F3 (shown in FIG. 45) are set in a zigzag array. Asshown in FIG. 41, on each comer section of the floating member 22, aguide pin 22b is formed to protrude downward. The guide pins 22 areslidably fitted in boss portions (not shown in the drawing) formed onthe base plate of the socket body 1. The floating member 22 is urgedupward by coil springs 23 (shown in FIG. 37) fitted on the guide pins22b. Furthermore, at each substantial comer of the floating member 22, ahook portion 22c is formed to protrude downward. Upward movement of thefloating member 22 is limited by engagement of ends of the hook portions22c with lock portions formed on the base plate of the socket body 1.

To the socket body 1, a plurality of outer contact pins 24 shown in FIG.42A, a plurality of middle contact pins 25 shown in FIG. 42B, and aplurality of inner contact pins 26 shown in FIG. 42C are fixed. Thecontact pins 24, 25, 26 are structured to have spring sections 24c, 25c,26c between free end sections having contact portions 24a, 25a, 26a tobe brought into contact with the lead terminals F1, F2, F3 of the TABpackage via the openings 22a of the floating member and base sections24b, 25b, 26b.

Each of the spring sections 24c, 25c, 26c of the contact pins 24, 25, 26has a vertical piece extending substantially vertically in an upwarddirection from an outer end of each of the base sections 24b, 25b, 26band a horizontal piece extending substantially horizontally in an inwarddirection relative to the socket body 1 from an upper end of thevertical piece. As shown in FIG. 37, the spring section 24c of the outercontact pin 24 is located above the spring section 25c of the middlecontact pin 25, and the spring section 26c of the inner contact pin 26is located below the spring section 25c of the middle contact pin 25.

Each of the free end sections, which form contact portions 24a, 25a,26a, of the contact pins 24, 25, 26 extends upward from an inner sideend of each of the horizontal pieces of the spring sections 24c, 25c,26c. To be precise, the free end section of the middle contact pin 25extends substantially vertically in an upward direction from the innerside end of the horizontal piece of the spring section 25c to the topend of the contact portion 25a, while the free end sections of the outerand inner contact pins 24, 26 extend substantially vertically in anupward direction from the inner side ends of the horizontal pieces ofthe spring sections 24c, 26c to the points in the vicinity of thecontact portions 24a, 26a but further extend in directions toward thetop end of the contact portion 25a of the contact pin 25 from thesepoints to their top ends of the contact portions 24a, 26a. Furthermore,the contact portions 24a, 25a, 26a of the contact pins 24, 25, 26 arearranged in three rows to form a zigzag array corresponding to thezigzag array of the lead terminals F1, F2, F3 of the TAB package.Specifically, as shown in FIG. 47 and FIG. 38, this embodiment adopts azigzag array such that an inner contact pin 26 and an outer contact pin24 are located adjacent to a middle contact pin 25 on respective sidesof the middle contact pin 25. Consequently, contact pins included in onerow keep a pitch width three times a pitch width p between adjacentcontact pins.

As shown in FIGS. 37, 38, 39, a core block 27 including layers of alower plate piece 28 and an upper plate piece 29, which are made ofsynthetic resin, is located under the floating member 22 and fixed onthe base plate of the socket body 1 with a rivet 30. Although the platepieces 28, 29 are layered without intervention of an airspace thusheight of the entire core block 27 is minimized, airspaces are allowedto be formed between a plurality of plate pieces. As shown in FIG. 38, aplurality of horizontal ribs 28a for regulating intervals between thebase sections 24b of the outer contact pins 24 in a row are integrallyformed on a lower surface of the lower place piece 28 at a pitch widththree times the pitch width p of an entire array of the contact pins 24,25, 26, a plurality of horizontal ribs 28b for regulating intervalsbetween the base sections 25b of the middle contact pins 25 in a row areintegrally formed on an upper surface of the lower plate piece 28 at thepitch width three times the pitch width p of the entire array of thecontact pins 24, 25, 26, and a plurality of horizontal ribs 29a forregulating intervals between the base sections 26b of the inner contactpins 26 in a row are integrally formed on an upper surface of the upperplate piece 29 at the pitch width three times the pitch width p of theentire array of the contact pins 24, 25, 26. As shown in FIG. 38, phasesof the pitch of the horizontal ribs 28a, 28b, 29a are orderly shiftedamong the corresponding surfaces of the plate pieces 28, 29 by the pitchwidth p of the entire array of the contact pins 24, 25, 26 in accordancewith the order of zigzag arrangement of the contact pins 24, 25, 26. Asshown in FIGS. 37-39 and FIG. 42A, on the base section 24b of each outercontact pin 24, integrally formed is a connecting terminal 24d forelectrical connection to an external circuit board (not shown in thedrawings). The connecting terminals 24d pierce the base plate of thesocket body 1 and a locating board 3 mounted on a rear surface of thebase plate through perforations formed therein, to protrude downwardfrom the locating board 3. As shown in FIG. 42A, the outer contact pins24 have their connecting terminals 24d selectively formed at an innerposition indicated by the solid line or at an outer position indicatedby the double dot & dash line, to be arranged by turns in a direction ofthe row of the outer contact pins 24. Similarly, each middle contact pin25 has a connecting terminal 25d protruding downward from the basesection 25b. The connecting terminals 25d pierce the lower plate piece28, the base plate of the socket body 1 and the locating board 3 throughperforations formed therein, to protrude downward from the locatingboard 3. As shown in FIG. 42B, the middle contact pins 25 also havetheir connecting terminals 25d selectively formed at an inner positionindicated by the solid line or at an outer position indicated by thedouble dot & dash line, to be arranged by turns in a direction of therow of the middle contact pins 25. Also, each inner contact pin 26 has aconnecting terminal 26d protruding downward from the base section 26b.The connecting terminals 26d pierce the upper plate piece 29, the lowerplate piece 28, the base plate of the socket body 1 and the locatingboard 3 through perforations formed therein, to protrude downward fromthe locating board 3. As shown in FIG. 42C, the inner contact pins 26also have their connecting terminals 26d selectively formed at an innerposition indicated by the solid line or at an outer position indicatedby the double dot & dash line, to be arranged by turns in a direction ofthe row of the inner contact pins 26. Consequently, according to thisembodiment, the connecting terminals 24d, 25d, 26d of the contact pins24, 25, 26 protrude downward from the locating board 3 to form a zigzagarray in six rows. However, another configuration is allowable where theconnecting terminals 24d, 25d, 26d of the contact pins 24, 25, 26protrude downward from the locating board 3 simply forming a zigzagarray in three rows.

As shown in FIGS. 37 and 39, on an outer side face of the lower platepiece 28, a plurality of vertical ribs 28c for regulating intervalsbetween the spring sections 24c of the outer contact pins 24, which areto be held to this face, are integrally formed at the pitch width threetimes the pitch width p of the entire array of the contact pins 24, 25,26; on an outer side face of the upper plate piece 29, a plurality ofvertical ribs 29b for regulating intervals between the spring sections25c of the middle contact pins 25, which are to be held to this face,are integrally formed at the pitch width three times the pitch width pof the entire array of the contact pins 24, 25, 26; and on an insideface of an enclosure wall of the socket body 1 also, a plurality ofvertical ribs 1t for regulating intervals between the spring sections24c of the outer contact pins 24, which are to be held to this face, areintegrally formed at the pitch width three times the pitch width p ofthe entire array of the contact pins 24, 25, 26.

As shown in FIGS. 46 and 47, an outer separator member 31 is providedbetween the free end sections of the outer contact pins 24 and the freeend sections of the middle contact pins 25, and an inner separatormember 32 is provided between the free end sections of the middlecontact pins 25 and the free end sections of the inner contact pins 26.As shown in FIGS. 43B, 44B, on an outer side face and an inner side faceof the outer separator member 31 respectively, pluralities of verticalribs 31a, 31b for regulating intervals of the free end sections of theouter and middle contact pins 24, 25 are integrally formed at the pitchwidth three times the pitch width p of the entire array of the contactpins 24, 25, 26. Also, as shown in FIGS. 43A, 44A, on an outer side faceand an inner side face of the inner separator member 32 respectively,pluralities of vertical ribs 32a, 32b for regulating intervals of thefree end sections of the middle and inner contact pins 25, 26 areintegrally formed at the pitch width three times the pitch width p ofthe entire array of the contact pins 24, 25, 26. As shown in FIGS. 37and 46, the vertical ribs 31b formed on the inner side face of the outerseparator member 31 are located above the vertical ribs 32a formed onthe outer side face of the inner separator member 32, and the free endsections of the middle contact pins 25 are engaged with the verticalribs 31b on the inner side face of the outer separator member 31 andwith the vertical ribs 32a on the outer side face of the inner separatormember 32.

Consequently, horizontal locations of the outer separator member 31 andthe inner separator member 32 are determined with respect to thedirection along the rows in the zigzag array of the contact pins via themiddle contact pins 25, with the further consequence that horizontallocations of the free end sections of the outer, middle and innercontact pins 24, 25, 26 are determined with respect to the directionalong the rows in the zigzag array of the contact pins via the separatormembers 31, 32.

Furthermore, vertical location of the outer separator member 31 isregulated by lower side abutting portions 24e protruding from an innerside of the free end sections of the outer contact pins 24 and upperside abutting portions 25e protruding from an outer side of the free endsections of the middle contact pins 25. Also, vertical location of theinner separator member 32 is regulated by upper abutting portions 25fprotruding from an inner side of the free end sections of the middlecontact pins 25 and lower side abutting portions 26e protruding from anouter side of the free end sections of the inner contact pins 26.

Since the IC socket described above is configured so that a core block27 including layers of a lower plate piece 28 and an upper plate piece29 is fixed to the base plate of the socket body 1 at a location underthe floating member 22, wherein a plurality of ribs (the horizontal ribs28a) for regulating intervals of the base sections 24b of the outercontact pins 24 are integrally formed on a surface selected out ofsurfaces of the two plate pieces 28, 29 to correspond to the row of theouter contact pins 24 (the lower surface of the lower plate piece 28), aplurality of ribs (the horizontal ribs 28b) for regulating intervals ofthe base sections 25b of the middle contact pins 25 are integrallyformed on a surface selected out of the surfaces of the two plate pieces28, 29 to correspond to the row of the middle contact pins 25 (the uppersurface of the lower plate piece 28), and a plurality of ribs (thehorizontal ribs 29a) for regulating intervals of the base sections 26bof the inner contact pins 26 are integrally formed on a surface selectedout of the surfaces of the two plate pieces 28, 29 to correspond to therow of the inner contact pins 26 (the upper surface of the upper platepiece 29), ribs 28a, 28b, 29a are allowed to have thickness greater thanthe pitch width p of the entire array of the contact pins 24, 25, 26.According to this embodiment, if the pitch width p of the entire arrayof the contact pins 24, 25, 26 is 0.2 mm and plate thickness of the pinsis 0.1-0.12 mm for example, pitch width of the ribs 28a, 28b, 29a comesto 0.6 mm thus 0.48-0.5 mm thickness is secured for the ribs 28a, 28b,29a. Since the base sections 24a, 25a, 26a of the contact pins 24, 25,26 are steadily held by the ribs 28a, 28b, 29a having thickness greaterthan the pitch width p of the entire array of the contact pins 24, 25,26, the contact pins 24, 25, 26 can be steadily fixed at a narrow pitchwidth not greater than 0.2 mm, free from problems concerning processingfineness or strength of the formed synthetic resin. Furthermore, sincephases of the pitch of the ribs 28a, 28b, 29a are orderly shifted amongthe selected surfaces of the plate pieces 28, 29 by the pitch width p ofthe entire array of the contact pins 24, 25, 26 in accordance with theorder of zigzag arrangement of the contact pins 24, 25, 26, uniformpitch width over the entire array of the contact pins 24, 25, 26 can beeasily obtained.

Furthermore, in the IC socket configured as described above, since thecore block 27 comprises the lower plate piece 28 having the horizontalribs 28a and the horizontal ribs 28b respectively formed on the upperand lower surfaces thereof and the upper plate piece 29 having thehorizontal ribs 29a formed on the upper surface thereof, number of theplate pieces required is less than number of rows in the zigzag array ofthe contact pins 24, 25, 26, thus number of parts and assemblies can bereduced. Also, the height of the entire core block 27 can be reduced torealize compact-sizing of the IC socket.

Furthermore, in the IC socket configured as described above, since thevertical ribs 28c, 29b for regulating respective intervals of the springsections 24c, 25c in the rows of the contact pins 24, 25 arerespectively formed on the outer side faces of the plate pieces 28, 29,to which the spring sections 24c, 25c are to be held, the springsections 24c, 25c of the contact pins 24, 25 can be stably supported bythe vertical ribs 28c, 29c on the outer side faces of the plate pieces28, 29, upon thickness of the vertical ribs 28c, 29c being secured to begreater than the pitch width of the entire array of the contact pins 24,25, 26. While the contact pins 24, 25 to be held to the outer side facesof the plate pieces 28, 29 are larger than the contact pins 26 in sizeof the spring section, specifically in length of the vertical piece andthus are more liable to warp horizontally, the vertical ribs 28c, 29bprevent such warp with great effect.

Furthermore, in the IC socket configured as described above, sincevertical ribs it for regulating intervals of the spring sections 24c inthe row of the outer contact pins 24 are formed on the inside face ofthe enclosure wall of the socket body 1, to which the vertical pieces24f of the spring section 24c are to be held, the vertical pieces 24f ofthe contact pins 24 can be stably supported by the vertical ribs 1t onthe inside face of the enclosure wall of the socket body 1, uponthickness of the vertical ribs 1t being secured to be greater than thepitch width of the entire array of the contact pins 24, 25, 26. Whilethe vertical pieces 24f of the outer contact pins 24 to be held to theinside face of the enclosure wall of the socket body 1 are longer thanthose of remaining contact pins 25, 26 and thus are more liable to warphorizontally, the vertical ribs it prevent such warp with great effect.

Furthermore, since the IC socket described above is configured so thatseparator members 31, 32 are respectively provided between the rows ofthe free end sections of the contact pins 24, 25, 26 arranged zigzag inthree rows, wherein pluralities of vertical ribs 31a, 31b, 32a, 32b forregulating respective intervals of the free end sections of the contactpins 24, 25, 26 which are arranged in their respective single rows onrespective two sides of the separator members 31, 32 are formed onrespective two side faces of the separator members 31, 32, the free endsections of the contact pins 24, 25, 26 arranged zigzag in three rowscan be stably supported, even if the pitch width p of the zigzag arrayis not greater than 0.2 mm, by the vertical ribs 31a, 31b, 32a, 32bformed on the side faces of the separator members 31, 32, upon thicknessof the vertical ribs 31a, 31b, 32a, 32b being secured to be greater thanthe pitch width p of the entire array of the contact pins 24, 25, 26.

Furthermore, since the IC socket described above is configured so thatupper side abutting portions (25e) are formed on ones of the free endsections of the contact pins 24, 25 arranged in their respective rows onrespective sides of the outer separator member 31 while lower sideabutting portions (24e) are formed on the others of the free endsections, thereby vertical location of the outer separator member 31being regulated, and upper side abutting portions (25f) are formed onones of the free end sections of the contact pins 25, 26 arranged intheir respective rows on respective sides of the inner separator member32 while lower side abutting portions (26e) are formed on the others ofthe free end sections, thereby vertical location of the inner separatormember 32 being regulated, the separator members 31, 32 can be easilyset in their positions between the rows of the contact pins 24, 25, 26arranged zigzag in three rows, and moreover, are allowed to bevertically displaced along with the free end sections of the contactpins 24, 25, 26.

FIG. 48 shows an example of another configuration of the core block 27according to this embodiment. The core block 27 in the drawing comprisesthree layers of plate pieces 33, 34, 35. On an upper surface of thelower plate piece 33, a plurality of horizontal ribs 33a for regulatingintervals of the base sections 24b of the outer contact pins 24, out ofthe contact pins 24, 25, 26 arranged zigzag in three rows, areintegrally formed at a pitch width three times a pitch width p of theentire array of the contact pins 24, 25, 26; on an upper surface of themiddle plate piece 34, a plurality of horizontal ribs 34a for regulatingintervals of the base sections 25b of the middle contact pins 25 areintegrally formed at the pitch width three times the pitch width p ofthe entire array of the contact pins 24, 25, 26; also, on an uppersurface of the upper plate piece 35, a plurality of horizontal ribs 35afor regulating intervals of the base sections 26b of the inner contactpins 26 are integrally formed at the pitch width three times the pitchwidth p of the entire array of the contact pins 24, 25, 26. Phases ofthe pitch of the horizontal ribs 33a, 34a, 35a are orderly shifted amongthe selected surfaces of the plate pieces 33, 34, 35 by the pitch widthp of the entire array of the contact pins 24, 25, 26 in accordance withthe order of zigzag arrangement of the contact pins 24, 25, 26.

In the configuration of the core block 27 shown in FIG. 48 also, thebase sections 24b, 25b, 26b of the contact pins 24, 25, 26 arrangedzigzag in three rows can be stably supported at a narrow pitch width pnot greater than 0.2 mm, upon thickness of the horizontal ribs 33a, 34a,35a formed on the upper surfaces of the plate pieces 33, 34, 35, beingsecured to be greater than the narrow pitch width p of the zigzag arrayof the contact pins 24, 25, 26. Also in this configuration, while asmany (three) plate pieces (33, 34, 35) as (three) rows of the zigzagarray of the contact pins 24, 25, 26 are required, shape of each of theplate pieces is simplified thus is convenient for processing.

While this example according to the embodiment configures the horizontalribs 33a, 34a, 35a to be formed on the upper surfaces of the platepieces 33, 34, 35, another configuration where similar horizontal ribsare formed on lower surfaces of the plate pieces 33, 34, 35 is possible.Also, if the contact pins are to be arranged zigzag in four or morerows, the layers of the plate pieces could be increased accordingly.

FIG. 49 shows another example of configuration of the core block 27according to this embodiment. The core block 27 in the drawing compriseslayers of a lower plate piece 28 and an upper plate piece 29. On a lowersurface of the lower plate piece 28, a plurality of horizontal ribs 28afor regulating intervals of the base sections 24b of outer contact pins24, out of the contact pins 24, 25, 26 arranged zigzag in three rows,are integrally formed at a pitch width four times a pitch width p of theentire array of the contact pins 24, 25, 26; on an upper surface of theupper plate piece 29, a plurality of horizontal ribs 29a for regulatingintervals of the base sections 26b of the inner contact pins 26 areintegrally formed at the pitch width four times the pitch width p of theentire array of the contact pins 24, 25, 26; also, on an upper surfaceof the lower plate piece 28 and a lower surface of the upper plate piece29, pluralities of horizontal ribs 28b, 29b for alternately regulatingintervals of the base sections 25b of the middle contact pins 25 areintegrally formed at the pitch width four times the pitch width p of theentire array of the contact pins 24, 25, 26. In short, two plate pieces28, 29 each having vertical ribs formed on both surfaces thereof areused in this configuration. Phases of the pitch of the horizontal ribs28a, 28b, 29a, 29b are orderly shifted among the corresponding surfacesof the plate pieces 28, 29 by the pitch width p of the entire array ofthe contact pins 24, 25, 26 in accordance with the order of zigzagarrangement of the contact pins 24, 25, 26.

In the configuration of the core block 27 shown in FIG. 49 also, thebase sections 24b, 25b, 26b of the contact pins 24, 25, 26 arrangedzigzag in three rows can be stably supported at a narrow pitch width pnot greater than 0.2 mm, upon thickness of the horizontal ribs 28a, 28b,29a, 29b formed on respective surfaces of the plate pieces 28, 29 beingsecured to be greater than the narrow pitch width p of the zigzag arrayof the contact pins 24, 25, 26. If, for comparison, number of thecontact pins in a zigzag array is supposed to be the same, greaterthickness is secured for the ribs 28a, 29b shown in FIG. 49 than for theribs 28a, 28b, 29a shown in FIG. 38 or the ribs 33a, 34a, 35a shown inFIG. 48. Therefore, this example of configuration allows specially finepitch width of the contact pins 24, 25, 26. Additionally, the supportingstructure of the base sections 24b, 25b, 26b shown in FIG. 49 does notprevent the contact portions 24a, 25a, 26a from being arranged as shownin FIG. 47.

FIG. 50 shows still another example of configuration of the core block27 according to this embodiment, to be used with contact pins arrangedzigzag in four rows. The core block 27 in the drawing comprises threelayers of plate pieces 36, 37, 38. On a lower surface of the lower platepiece 36, a plurality of horizontal ribs 36a for regulating intervals ofthe base sections 39b of first contact pins 39 in an outermost row, outof contact pins 39, 40, 41, 42 arranged zigzag in four rows, areintegrally formed at a pitch width four times a pitch width p of theentire array of the contact pins 39, 40, 41, 42; on a lower surface ofthe middle plate piece 37, a plurality of horizontal ribs 37a forregulating intervals of the base sections 40b of the second contact pins40 are integrally formed at the pitch width four times the pitch width pof the entire array of the contact pins 39, 40, 41, 42; on an uppersurface of the middle plate piece 37, a plurality of horizontal ribs 37bfor regulating intervals of the base sections 41b of the third contactpins 41 are integrally formed at the pitch width four times the pitchwidth p of the entire array of the contact pins 39, 40, 41, 42; and onan upper surface of the upper plate piece 38, a plurality of horizontalribs 38a for regulating intervals of the base sections 42b of the fourthcontact pins 41 in an innermost row are integrally formed at the pitchwidth four times the pitch width p of the entire array of the contactpins 39, 40, 41, 42. Phases of the pitch of the horizontal ribs 36a,37a, 37b, 38a are orderly shifted among the selected surfaces of theplate pieces 36, 37, 38 by the pitch width p of the entire array of thecontact pins in accordance with the order of zigzag arrangement of thecontact pins 39-42.

In this configuration also, the base sections 39b-42b of the contactpins 39-42 arranged zigzag in four rows can be stably supported at anarrow pitch width p not greater than 0.2 mm, upon thickness of thehorizontal ribs 36a, 37a, 37b, 38a formed on the selected surfaces ofthe plate pieces 36, 37, 38 being secured to be greater than the narrowpitch width p of the zigzag array of the contact pins 39-42.

FIG. 51 shows an example of configuration of supporting structure forthe free end sections of the contact pins with the separator members inthe case of the contact pins being arranged zigzag in four rows. Asshown in the drawing, separator members 43, 44, 45 are respectivelyprovided between the rows of the free end sections, which form contactportions 39a, 40a, 41a, 42a at ends thereof, of the contact pins 39, 40,41, 42 arranged zigzag in four rows, and pluralities of vertical ribs43a, 43b, 44a, 44b for regulating respective intervals of the free endsections of the contact pins 39, 40, 41, 42 which are arranged in theirrespective single rows on respective two sides of the separator members43, 44, 45 are formed on respective two side faces of the separatormembers 43, 44, 45. Furthermore, upper side abutting portions 40e, 40f,41e are formed on free end sections of contact pins arranged on one sideof respective separator members 43, 44, 45 while lower side abuttingportions 39e, 41f, 42e are formed on free end sections of contact pinsarranged on the other, thereby vertical location of the outer separatormembers 43, 44, 45 being regulated. Therefore, the free end sections ofthe contact pins 39-42 arranged zigzag in four rows can be stablysupported at a narrow pitch width p not greater than 0.2 mm, uponthickness of the vertical ribs 43a, 43b, 44a, 44b, 45a, 45b formed onthe separator members 43, 44, 45 being secured to be greater than thenarrow pitch width p of the zigzag array of the contact pins 39-42.

The foregoing description has been made only on some examples of theconfigurations according to this embodiment. It is to be understood thatthis embodiment can be variously modified in the scope of the invention,not limited to these configurations. For example, the core block isallowed to comprise three layers of plate pieces each formingpluralities of horizontal ribs on upper and lower surfaces thereof at apitch width six times the pitch width of the contact pins arrangedzigzag in four rows, for supporting the base sections of the contactpins.

The shape of the floating member 46 is illustrated in detailspecifically in FIG. 53. On the lower side of the floating member 46,guide pins 46a are formed in the vicinity of overhangs provided at thefour corners. The guide pins 46a are slidably fitted in guide holes notshown in the drawings but formed on the socket body 1 to make thefloating member 46 movable vertically in the state shown in FIG. 52. Thefloating member 46 is urged upward by coil springs 23 partiallyappearing in FIG. 54, but its upward movement is limited by engagementof four flexible hook portions 46b with the socket body 1.

As shown in FIG. 53A, four through slots 46c are formed in the floatingmember 46 along four sides thereof. Each slot 46c has rows of ribsformed at regular intervals on both edges along its longitudinaldirection. Phases of the regular arrangement of the ribs 46d formed onthe outer edge and the ribs 46e formed on the inner edge are mutuallyshifted.

The structure for supporting contact pins is shown in FIG. 54 utilizingthe same symbols in FIGS. 37-39 for the same members. Since thisstructure has been detailed referring to FIGS. 37-39, explanation willbe omitted to avoid redundancy.

Now, referring to FIGS. 55A-55C, shapes of the contact pins will bedescribed. An inner contact pin 26 shown in FIG. 55A has a connectingterminal 26d formed on a lower side of a L-shaped base section 26bthereof for connection with an external circuit, and a free end section,which has a contact portion 26a at an end thereof, formed on an upperside of the base section 26b with intervention of a spring section 26cwhich is vertically bending. There are two types of the inner contactpins 26; the connecting terminals 26d are selectively formed at an innerposition indicated by the solid line or at an outer position indicatedby the double dot & dash line. A middle contact pin 25 shown in FIG. 55Balso has a connecting terminal 25d formed on a lower side of a L-shapedbase section 25b thereof, and a spring section 25c and a free endsection, which has a contact portion 25a at an end thereof, formed on anupper side of the base section 25b. On the free end section of themiddle contact pin 25, a protrusion 25g also is formed. There are twotypes of the middle contact pins 25; the connecting terminals 25d areselectively formed at an inner position indicated by the solid line orat an outer position indicated by the double dot & dash line. An outercontact pin 24 shown in FIG. 55C has, similar to the inner contact pin26, a base section 24b, a connecting terminal 24d, a spring section 24cand a free end section having a contact portion 24a at an end thereof.There are two types of the outer contact pins 24; the connectingterminals 24d are selectively formed at an inner position indicated bythe solid line or at an outer position indicated by the double dot &dash line.

Since arrangement of the contact pins in relation to the plate pieces28, 29 has already been described referring to FIGS. 37-39, explanationwill be omitted.

Now, Referring to FIGS. 56-58, configuration for regulating locations offree end sections of the contact pins 26, 25, 24 using the floatingmember 46 will be described. FIG. 56 is a plan view of the separatormember 47. As shown in the drawing, the separator member 47 forms ribs47a arranged on a left side face thereof in one row at regularintervals, and ribs 47b regularly arranged on a right side face thereofin one row at the same pitch width as the ribs 46a with a phase of thepitch shifted by one third of the pitch width from the phase of thepitch of the ribs 47a. A row of the free end sections of the middlecontact pins 25 are made engaged with the ribs 47a and a row of the freeend sections of the outer contact pins 24 are made engaged with the ribs47b, thereby the separator member 46 being held by and between the rowsof the contact pins 24, 25. Therefore, as shown in FIG. 58, theprotrusions 25g of the contact pins 25 are allowed to keep the separatormember 47 from being displaced downward relative to the contact pins.

At the ends of the free end sections, the contact portions 26a of theinner contact pins 26 are engaged with the ribs 46e of the floatingmember 46 and the contact portions 24a of the outer contact pins 24 areengaged with the ribs 46d, while the middle contact pins 25a are justinserted into the slot 46c of the floating member without engagementwith any ribs. As a result, all the contact pins are arranged so thatthe contact portions thereof are positioned at regular intervals inthree rows with a phase of the pitch of one row being shifted fromanother row in a direction of the rows by one third of the pitch widthof each row, to allow the IC socket to be applied to the TAB packagehaving lead terminals F1, F2, F3 arranged zigzag in three rows as shownin FIG. 45.

Furthermore, since this configuration allows contact pins in each row tobe sufficiently spaced among each other, mutual contact between adjacentpins in the row is impossible. Similarly, since this configuration doesnot require each row of ribs to have an extremely fine pitch, integralforming of each row of ribs out of synthetic resin is facilitated.Moreover, since no ribs for the contact portions 25a of the contact pins25 are required to be formed on the floating member 46 as apparentlyseen in FIG. 57, this configuration is further advantageous with respectto the forming process of the floating member 46 also.

Since contact pins are made of thin plate material, force is oftenproduced to warp them in a horizontal direction, i.e. directionperpendicular to the figure surface in FIG. 58 as the contact portionsare pushed during loading of the TAB package. As for the contact pins26, contact portions 26a are engaged with the ribs 46e to be lessaffected by the force. As for the contact pins 25, no row of ribs areprovided to be engaged with the contact portions 25a, thus the force isapplied to the contact portions 25a to shift them from their positionswhich correspond to the lead terminals F2 of the TAB package. However,according to this embodiment, locations of the rows of the contact pins25, 26 are mutually regulated with intervention of the separator member47, and the contact portions 24a of the contact pins 24 are engaged withthe ribs 46d of the floating member 46. Therefore, the contact portions25a are not substantially affected by the horizontal force.

As understood from the foregoing description, according to thisembodiment as applied to the IC socket having contact pins arranged in aplurality of rows, contact portions of contact pins in one row areinserted into the slot of the floating member 46 without engagement witha row of ribs formed on the floating member, thereby minimizing anecessary number of rows of ribs formed on the floating member 46.Furthermore, the row of the contact pins not engaged with the ribs onthe floating member 46 and a row of contact pins engaged with a row ofribs on the floating member 46 are configured to hold the separatormember 47 therebetween for the purpose of stably locating the contactportions in the slot. To attain the same purpose, the separator member47 is allowed to be held between the contact pins 26 and the contactpins 25. In this alternative configuration, however, protrusions similarto the protrusions 25g have to be formed either on left sides of thecontact pins 25 or on right sides of the contact pins 26.

Although in the foregoing, this embodiment is described as applied tothe IC socket provided with three rows of contact pins, this isapplicable to an IC socket having two rows of contact pins also bychanging the configuration in FIG. 58 so that the contact pins 26 areremoved. In this case, the ribs 36e are not necessary, but the phaseshift between the rows of ribs formed on the separator member 27, platepieces 28, 29. etc. should be modified to be one half of the pitch widthof each row.

If this embodiment is to be applied to an IC socket having four rows ofcontact pins, the configuration shown in FIG. 58 will be changed so thatone additional row of contact pins are provided between the row of thecontact pin 26 and the row of the contact pins 25 to be inserted in theslot 46c. In this modified configuration, an additional separator memberintervenes between the row of the contact pins 26 and the fourth row ofthe contact pins as a matter of course, and in some cases, a thirdseparator member may be further added to intervene between the fourthrow of the contact pins and the row of the contact pins 25. Also, thephase shift between the ribs becomes one fourth of the pitch width ofeach rib.

Furthermore, if the above described two configurations are combined, ICsocket having five rows of contact pins is realized. If the abovementioned configuration for the contact pins arranged in three rows isdoubled, an IC socket having the contact pins arranged in six rows isrealized. And if necessary, it is possible to arrange contact pins inmore rows.

Next, the description will be made on an example of modification of thisembodiment. This example is different only in relationship between thecontact pins and the separator member. Thus, only this difference isexplained using FIGS. 59-60. FIG. 59 is a view showing relationshipamong the floating member, contact pins and the separator member. FIG.60 is a sectional view taken along the line LX--LX of FIG. 59. As shownin FIG. 59, on respective side faces of the separator member 47, aplurality of ribs 47a and a plurality of ribs 47b are formed at regularintervals, and in the center of the separator member, a plurality ofthrough holes 47c are arranged in parallel with rows of the ribs 47a,47b. Phase of the pitch of the holes 47b is shifted relative to the ribs47a by one third of the pitch width in one direction and is shiftedrelative to the ribs 47b by one third of the pitch width in the oppositedirection. The contact pins 25 are provided with protrusions 25h inaddition to the protrusions 25g as shown in FIG. 60, because in usingsuch a separator member 47, means for maintaining a positionalrelationship between the contact pins and the separator member to allowsmooth sliding between the contact pins 26 and the rib 47a inengagement, between the contact pins 25 and the holes 47c in fittingcondition, and between contact pins 24 and the ribs 47b in engagement isindispensable. The protrusions 25h are allowed to be replaced by similarprotrusions formed on the contact pins 26 as a matter of course.

Although in this modified embodiment, the contact portions 26a, 24a ofthe contact pins 26, 24 are engaged with the rows of ribs 46e, 46d ofthe floating member 46 respectively, some cases allow one of the rows ofthe contact portions 26a, 24a to be just inserted into the slit 46c withonly the other row of the contact portions engaged with one row of theribs on the floating member. In such a case, the floating member 46 isstructured to have only one row of ribs formed on one edge of the slot46c along its longitudinal direction. Furthermore, this modifiedembodiment also is applicable to an IC socket having contact pinsarranged in five or six rows.

Next, another example of modification of this embodiment will bedescribed using FIG. 61. In the drawing, the contact pins 26 and thecontact pins 25 hold a separator member 48 having an L-shaped transversesection therebetween. On respective sides of the separator member 48, aplurality of L shaped ribs 48a and a plurality of ribs 48b are regularlyarranged. The ribs 48b and the ribs 47a of the separator member 47 areto have the same phase of arrangement in the assembled condition. Phasesof the pitch of the ribs 48a, the ribs 47a (or the ribs 48b), and theribs 47b are orderly shifted by one third of the pitch width.

Since the separator member 48 has an L-shaped transverse section and isheld by correspondingly shaped portions of the contact pins 25, 26therebetween, means such as protrusions 25h are not necessary. Ofcourse, no reason prevents the L-shaped transverse section from beingapplied to the separator member 47 instead of the separator member 48,or from being applied to both of the separator members 47, 48.

Although in this modified embodiment the contact portions 26a, 24a ofthe contact pins 26, 24 are engaged with the rows of ribs 46e, 46d ofthe floating member 46 respectively, some cases allow one of the rows ofthe contact portions 26a, 24a to be just inserted into the slit 46c withonly the other row of the contact portions engaged with one row of theribs on the floating member, as in the above described modifiedembodiment.

In the foregoing descriptions on this embodiment and its modifications,explanation has been made based on the configuration in which at leastone row of the contact portions of the contact pins are engaged with theribs formed on the floating member. However, instead of the row of ribs,rows of holes are allowed to be formed on the floating member 46, sothat the contact portions are fitted therein. Furthermore, thisembodiment is applicable not only to the IC socket for the TAB packageshaving lead terminals arranged on its four sides, but also to IC socketsfor various electronic devices such as IC, LSI devices.

Next, description will be made on an example of modification of theembodiment which has been described referring to FIGS. 21-36F. FIG. 62Ashows a main part of this modified configuration, FIG. 62B is asectional view taken along LXII--LXII of FIG. 62A, and FIG. 62C is aright-side view of FIG. 62B.

According to this modified embodiment, pluralities of ribs 48a, 48b arearranged at regular intervals on upper and lower surfaces of the coreblock 48 respectively. However, positional relationship between theupper side ribs 48a and the lower side ribs 48b is different from thataccording to the configuration already described; phases of pitch of theribs 48a, 48b are not shifted from each other.

Moreover, on an outer side face of the core block 48, ribs 48c areformed at regular intervals so that the ribs 48a and the ribs 48b arecontinuously linked with intervention of these ribs 48c.

Each first contact pin 49 of this modified embodiment has a connectingterminal 49b which is arranged on a substantially J-shaped base section49a formed as one leg. Between the base section 49a and a free endsection 49c formed as the other leg, a spring section 49d is formed. Atan end of a vertically rising piece of the free end section 49c, acontact portion 49e is formed. Each second contact pin 50 has aconnecting terminal 50b arranged on a substantially J-shaped basesection 50a formed as one leg. Between the base section 50a and a freeend section 50c formed as the other leg, a spring section 50d is formed.At an end of a vertically rising piece of the free end section 50c, acontact portion 50c is formed. Also, as shown in the drawings, a risingpiece of the base section 50a forms a cranked portion 50f.

The first contact pins 49 are fixed to the core block 48 in such amanner that the base sections 49a are fitted in grooves between the ribs48a with the connecting terminals 49b being inserted into holes formedin the core block 48. The second contact pins 50 are fixed to the coreblock 48 in such a manner that the base section 50a are fitted ingrooves between continuous ribs including the ribs 48b, 48c with theconnecting terminals 50b being inserted into perforations formed in thesocket body 1. Consequently, the contact portions 49e, 50e form anzigzag array as shown in FIG. 62A, while the ribs 48a and the ribs 48bare arranged without phase shift. Since the free end sections 49c, 50cof the contact pins 49,50 are located at different levels as shown inFIG. 62B, mutual contact between these contact pins is not caused evenif the contact pins are warped or distorted.

Next, referring to FIGS. 63A-63C, another example of modification of theembodiment of FIGS. 21-36F will be explained. This modification is, aswell as the above described example, unique in the configuration withrespect to the contact pins and the core block to which the contact pinsare fixed. Other configurations of this modification is identical tothose of the embodiment already described using 21-36F, thus will not bedetailed. FIG. 63A shows a main part of this modified configuration,FIG. 63B is a sectional view taken along LXIII--LXIII of FIG. 63A, andFIG. 63C is a right-side view of FIG. 63B.

According to this modified embodiment, pluralities of ribs 51a, 51b arearranged at regular intervals on upper and lower surfaces of the coreblock 51 respectively. Positional relationship between the upper sideribs 51a and the lower side ribs 51b is the same as the configurationaccording to the above described example; phases of pitch of the ribs51a, 51b are not shifted from each other. Also, on an outer side face ofthe core block 51, ribs 51c are formed at regular intervals so that theribs 51a and the ribs 51b are continuously linked with intervention ofthese ribs 51c.

According to this modified embodiment, first contact pins 52 have a sameshape as that of the first contact pins 49 of the above describedexample, while second contact pins 53 are not provided with such crankedportions as found in the second contact pins 50 of the above describedexample. The contact pins 52, 53 are provided with base sections 52a,53a, connecting terminals 52b, 53b, free end sections 52c, 53c, springsections 52d, 53d, and contact portions 52e, 53e also.

The first contact pins 52 and the second contact pins 53 are fixed tothe core block 51 in the same manner as described for the example above.Consequently, the contact portions 52e, 53e are arranged not alternatelybut in parallel as shown in FIG. 63A. Since the free end sections 52c,53c of the contact pins 52, 53 are located at different levels as shownin FIG. 63B, mutual contact between these contact pins is not causedeven if the contact pins are warped or distorted. Furthermore, accordingto this example of modified embodiment, intervals between the firstcontact pins 52 in themselves and intervals between the second contactpins 53 in themselves are allowed to be twice as wide as the intervalbetween adjacent first and second contact pins 49, 50 according to theabove example. Therefore, mutual contact in the first contact pins 52and mutual contact in the second contact pins 53 can be avoided withfiner arrangement of the contact portions being attained.

Next, referring to FIGS. 64A-64C, still another example of modificationof the embodiment of FIGS. 21-36F will be explained. This modificationis, as well as the above described examples, unique in the configurationwith respect to the contact pins and the core block to which the contactpins are fixed. Other configurations of this modification is identicalto those of the embodiment already described using 21-36F, thus will notbe detailed. FIG. 64A shows a main part of this modified configuration,FIG. 64B is a sectional view taken along LXIV--LXIV of FIG. 64A, andFIG. 64C is a right-side view of FIG. 64B.

According to this modified embodiment, pluralities of ribs 54a, 54b arearranged at regular intervals on upper and lower surfaces of the coreblock 54 respectively. Positional relationship between the upper sideribs 54a and the lower side ribs 54b is the same as the configuration ofthe embodiment of FIGS. 21-36F; phases of pitch of the ribs 51a, 51b areshifted by one half of the pitch width from each other. Also, on anouter side face of the core block 54, ribs 54c are formed at regularintervals to be continuously linked to the ribs 54b.

According to this modified embodiment, first contact pins 55 have a sameshape as that of the first contact pins 49, 52 of the above describedexamples, while second contact pins 56 are provided with crankedportions 56f formed by bending in a direction opposite to the bendingdirection of the cranked portions 50f of the second contact pin 50 ofthe first example described above. The contact pins 55, 56 are providedwith base sections 55a, 56a, connecting terminals 55b, 56b, free endsections 55c, 56c, spring sections 55d, 56d, and contact portions 55e,56e also.

The first contact pins 55 are fixed to the core block 54 in the samemanner as described for the above examples. The second contact pins 56are fixed to the core block 54 in such a manner that the base section56a are fitted in grooves between continuous ribs including the ribs54b, 54c. Consequently, the contact portions 55e, 56e are arranged notalternately but in parallel as shown in FIG. 64A in spite that thephases of the pitch of the ribs 54a, 54b are shifted from each other.Since the free end sections 55c, 56c of the contact pins 55, 56 arelocated at different levels as shown in FIG. 64B, mutual contact betweenthese contact pins is not caused even if the contact pins are warped ordistorted.

Through the foregoing descriptions on the embodiments and theirmodifications according to the present invention, the TAB package hasbeen referred to as an IC device to be loaded in the IC socket of thepresent invention. However, not limited to the TAB package, the presentinvention is also applicable to IC sockets for QFP type IC device,various kinds of IC packages, and such a device as has lead terminalsarranged on two sides of its IC chip. Furthermore, although theforegoing discussions have been made based on the condition that the ICdevice to be loaded in the IC socket has finely arranged lead terminals,it is needless to say that the present invention can be reduced toembody IC sockets for IC devices having lead terminals arranged at anordinary pitch width.

What is claimed is:
 1. An IC socket comprising:a socket body; a covercombinable with said socket body for loading an IC device at apredetermined position in said socket body; a floating member mounted tosaid socket body so as to be vertically displaceable relative thereto,said floating member having a first ribs-row and a second ribs-rowfacing said first ribs-row, said first ribs-row including a multitude ofribs arranged at regular intervals, said second ribs-rows including amultitude of ribs arranged at regular intervals as interrib intervals ofsaid first ribs-row with a phase shifted from the ribs in said firstribs-row; a plurality of core members fixed to said socket body atlocations under said floating member, each of said core members having afirst mount face and a second mount face; a plurality of first contactpins each having a free end section forming a contact portion, a basesection having a connecting terminal, and a spring section formedbetween said free end section thereof and said base section thereof, thefree end sections of said first contact pins being fitted between theribs in said first ribs-row, the base sections of said first contactpins being mounted to the first mount faces of said core members; and aplurality of second contact pins each having a free end section forminga contact portion, a base section having a connecting terminal, and aspring section formed between said free end section thereof and saidbase section thereof, the free end sections of said second contact pinsbeing fitted between the ribs in said second ribs-row, the base sectionsof said second contact pins being mounted to the second mount faces ofsaid core members.
 2. An IC socket according to claim 1, wherein thecontact portions of said first contact pins and the contact portions ofsaid second contact pins are arranged in one row.
 3. An IC socketaccording to claim 1, wherein the contact portions of said first contactpins and the contact portions of said second contact pins are arrangedin separate rows to form a zigzag array as a whole.
 4. An IC socketaccording to any one of claims 1 through 3, wherein said core membersextend in parallel with the first and second ribs-rows of said floatingmember, and arranged to surround the IC device loaded.
 5. An IC socketaccording to any one of claims 1 through 3, wherein said first mountface and said second mount face of each of said core members arerespectively formed on a pair of surfaces opposite to each other of thecore member.
 6. An IC socket according to any one of claims 1 through 3,wherein said first mount face and said second mount face of each of saidcore members are formed on one surface of the core member.
 7. An ICsocket according to any one of claims 1 through 3, wherein each of saidcore members includes a first block piece and a second block piece whichis arranged above said first block piece with a predetermined airspacekept therefrom.
 8. An IC socket according to any one of claims 1 through3, wherein said floating member includes a first floating piece havingsaid first ribs-row and a second floating piece having said secondribs-row, said first floating piece being mounted to said socket body soas to be displaceable relative thereto, said second floating piece beingintegrally fixed to said first floating piece.
 9. An IC socket accordingto claim 8, wherein said first floating piece and said second floatingpiece are mounted to a vertically extending pin member provided for saidsocket body, said pin member being configured as a reference pin usedfor positioning of the IC device when loaded.
 10. An IC socketcomprising:a socket body; a cover combinable with said socket body forloading an IC device at a predetermined position in said socket body; afloating member mounted to said socket body so as to be verticallydisplaceable relative thereto and having a plurality of openingsassigned to a plurality of terminal regions of the IC device, on each ofthe terminal regions a multitude of lead terminals being arranged zigzagin three or more rows; a plurality of contact pins each having a freeend section forming a contact portion to be brought into contact with alead terminal of the IC device through each of said openings of saidfloating member, a base section, and a spring section formed betweensaid free end section and said base section, said plurality of contactpins being arranged so that the contact portions thereof form a zigzagarray in three or more rows; and a plurality of core members fixed tosaid socket body at locations under said floating member; wherein eachof said core members includes a plurality of plate pieces layered, andon a surface selected out of surfaces of said plate pieces to beassigned to each row in the zigzag array of the contact pins, aplurality of ribs for regulating intervals of the base sections of thecontact pins arranged in each row are formed.
 11. An IC socket accordingto claim 10, wherein phases of pitch of said plurality of ribs areorderly shifted among the selected surfaces of said plate pieces by apitch width of the zigzag array of the contact pins in accordance withan order of the zigzag array of the contact pins.
 12. An IC socketaccording to claim 10, wherein each of said core members compriseslayers of a first plate piece forming the ribs on upper and lowersurfaces thereof, and a second plate piece forming the ribs on an upperor lower surface thereof.
 13. An IC socket according to claim 10,wherein each of said core members comprises layers of a plurality ofplate pieces each forming the ribs on an upper or lower surface thereof.14. An IC socket according to claim 10, wherein each of said coremembers comprises layers of a plurality of plate pieces each forming theribs on upper and lower surfaces thereof.
 15. An IC socket according toclaim 10, wherein on an outer side face of each of said plate pieces, aplurality of vertical ribs for regulating intervals of the springsections of the contact pins arranged in a row which is to be held toeach of said outer side faces are formed.
 16. An IC socket according toclaim 10 or 15, wherein said socket body comprises a base plate formounting said core members and an enclosure wall for enclosing outersides of said core members, an inside face of said enclosure wallforming a plurality of vertical ribs for regulating intervals of thespring sections of the contact pins arranged in a row which is to beheld thereto.
 17. An IC socket according to claim 10, wherein aseparator member is provided between each adjacent rows of the free endsections of the contact pins, each of two side faces of each of saidseparator members forming a plurality of vertical ribs for regulatingintervals of the contact portions of the contact pins arranged in a rowon each side of each separator member.
 18. An IC socket according toclaim 17, wherein the free end sections of the contact pins in a rowarranged on one side of each of the separator members are provided withupper side abutting portions which are allowed to meet a top surface ofeach of the separator members, and the free end sections of the contactpins in a row arranged on the other side of each of the separatormembers are provided with lower side abutting portions which are allowedto meet a bottom surface of each of the separator members, each of theseparator members being held by said upper side abutting portions andsaid lower side abutting portions.
 19. An IC socket comprising:a socketbody; a cover combinable with said socket body for loading an IC deviceat a predetermined position in said socket body; a floating membermounted to said socket body so as to be vertically displaceable relativethereto and having a plurality of openings; a plurality of core membersfixed to said socket body at locations under said floating member; and aplurality of contact pins, each of which is substantially U-shaped ashaving a first leg forming a contact portion to be brought into contactwith a lead terminal of the IC device through the opening of saidfloating member, a second leg having a connecting terminal for anexternal circuit, and a spring section formed between said first leg andsaid second leg; wherein the contact portions of said plurality ofcontact pins are arranged in separate rows to form a plurality ofpins-rows; wherein each of said core members have a plurality of mountfaces, with contact pins in different pins-rows being mounted ondifferent mount faces; and wherein positions of the first legs of saidplurality of contact pins are shifted among the pins-rows in a directionsubstantially parallel to each of the pins-rows.
 20. An IC socketaccording to claim 19, wherein every one of said plurality of contactpins are shaped to have a substantially same interval between the firstleg and the second leg thereof.
 21. An IC socket according to claim 19,wherein the contact pins in at least one of the plurality of pins-rowsare shaped to be different from the contact pins in another pins-rowwith respect to interval between the first leg and the second leg. 22.An IC socket according to any one of claims 19 through 21, wherein amount face of each of said core members have a multitude of first ribsso that the second legs of the contact pins that form one pins-row arefitted between said first ribs, and another mount face of each of saidcore members have a multitude of second ribs so that the second legs ofthe contact pins that form another pins-row are fitted between saidsecond ribs.
 23. An IC socket according to claim 22, wherein said firstribs are formed so that phases thereof are shifted from phases of saidsecond ribs.
 24. An IC socket according to claim 22, wherein said firstribs are formed without phase shift from said second ribs.
 25. An ICsocket according to claim 24, wherein the contact portions of thecontact pins are arranged in a plurality of rows to form a zigzag array.26. An IC socket comprising:a socket body; a cover combinable with saidsocket body for loading an IC device at a predetermined position in saidsocket body; a floating member mounted to said socket body so as to bevertically displaceable relative thereto and having a plurality ofopenings; a plurality of core members fixed to said socket body atlocations under said floating member, each of said core members having aplurality of mount faces; and a plural sets of contact pins, each of thesets including a multitude of contact pins, each contact pin having afree end section forming a contact portion, a base section having aconnecting terminal, and a spring section formed between said free endsection thereof and said base section thereof, the contact portions ofsaid contact pins being allowed to come into contact with lead terminalsof the IC device through said plurality of openings; wherein for each ofsaid plurality of core members, contact pins included in one of saidplural sets of contact pins are mounted on one of said plurality ofmount faces, and contact pins included in another at least one set ofsaid plural sets of contact pins are mounted on another mount face ofsaid plurality of mount faces.